Young Researcher Meeting

11th Young Researcher Meeting, Trento 2021 – Program

  • Monday 6 Sep 2021
  • Tuesday 7 Sep 2021
  • Wednesday 8 Sep 2021
  • Thursday 9 Sep 2021

Monday 6 Sep 2021

9:00 am - 1:30 pm Day 1 - Morning session

9:00 am - 10:00 am Invited speaker

Elusive in Cosmo

Martina Gerbino

Martina Gerbino is an INFN Researcher and Associate Professor at the University of Ferrara. Martina obtained her Ph.D. in Physics at the University of Rome "Sapienza". She then carried out research activities as a postdoc at the Oskar Klein Centre for Cosmoparticle Physics (OKC) in Stockholm and at Argonne National Laboratory (ANL) in the United States. Martina is a theoretical physicist working at the intersection of theory and observations. Her activity is focused on the study of fundamental physics properties through the interpretation of cosmological observations, with a particular interest in neutrino physics and, in general, in the cosmos. general, for the cosmo-particle field. Martina is an expert in the analysis and phenomenological interpretation of data obtained from CMB observations. She has been a member of the Planck Collaboration and is currently a member of the Simons Observatory, LiteBIRD, Euclid, LSPE, CMB-S4 collaborations.
Mon 9:00 am - 10:00 am

10:00 am - 10:25 am A new cosmological standard ruler: the Linear Point

A new cosmological standard ruler: the Linear Point

Stefano Anselmi

Baryon Acoustic Oscillations (BAO) are one of the most useful and used cosmological probes to measure cosmological distances independently of the underlying background cosmology. However, in the current measurements, the inference is done using a theoretical clustering correlation function template where the cosmological and the non-linear damping parameters are kept fixed to fiducial LCDM values. How can we then claim that the measured distances are model- independent and so useful to select cosmological models? Motivated by this compelling question we introduce a rigorous tool to measure cosmological distances without assuming a specific background cosmology: the “Purely-Geometric-BAO”. I will explain how to practically implement this tool with clustering data. This allows us to quantify the effects of some of the standard measurements’ assumptions. However, the inference is still plagued by the ambiguity of choosing a specific correlation function template to measure cosmological distances. We address this issue by introducing a new approach to the problem that leverages a novel BAO cosmological standard ruler: the “Linear Point”. Its standard ruler properties allow us to estimate cosmological distances without the need of modeling the poorly-known late-time nonlinear corrections to the linear correlation function. Last but not least, it also provides smaller statistical uncertainties with respect to the correlation function template fit.
Mon 10:00 am - 10:25 am

10:25 am - 10:50 am New estimators for anisotropic birefringence from CMB observations.

New estimators for anisotropic birefringence from CMB observations.

Matteo Billi

Cosmic birefringence (CB), i.e. the in vacuo rotation of the linear polarisation direction of a photon during propagation, is a tracer for new parity-violating interactions beyond the standard model of particle physics. This phenomenon can be driven by a cosmological pseudoscalar field coupled to the electromagnetism. Several astrophysical sources of linearly polarised photons can be used to investigate this effect. Among these sources, we focus on the oldest one of the Universe, i.e. the Cosmic Microwave Background (CMB) radiation, which is linearly polarised because of Thomson scattering. The CB rotation mixes the Q and U Stokes parameters and consequently the E- and B-mode polarisation. So if it is present this effect turns on the TB and EB cross- correlation between temperature and polarisation CMB power spectra, which are expected to be null in the standard scenario. Note that Cosmic Birefringence can be isotropic, when a single angle is enough to describe the all-sky phenomenon, and anisotropic, when the rotation depends on the direction of observations and therefore the phenomenon will be characterised by a map of angles. Current estimates for both isotropic and anisotropic birefringence are compatible with null effect. However, a recent analysis on Planck 2018 data lead by Minami and Komatsu provides an hint of detection for the isotropic birefringence at the level of 2.4σ.σ. In this talk, after presenting the main equations relating the birefringence effect to the observed CMB angular power spectra, we show how to build harmonic-based estimators sensitive to the features of this phenomenon. Starting from the observed CMB spectra we derive expressions useful to estimate the isotropic birefringence angle, the variance and the angular power spectrum of the birefringence anisotropies. In particular, we present the formalism for a novel statistical technique aimed at estimating the anisotropic birefringence effect from the observed CMB spectra. After a description of the algrebraic properties of this new methodology, we numerically validate the implementation in a Python code with realistic simulations and present preliminary constraints obtained from recent Planck 2018 data.
Mon 10:25 am - 10:50 am

10:50 am - 11:15 am Searching for parity violating electromagnetism with patches of the CMB sky

Searching for parity violating electromagnetism with patches of the CMB sky

Marco Bortolami

The Standard Model (SM) of Particle Physics predicts that the electromagnetic (EM) interaction respects the parity symmetry. An extension to the SM via an ad- dition of a Chern-Simons term to the EM lagrangian opens for new parity violating Physics that results in the Cosmic Birefringence (CB) effect. This effect is the in- vacuo rotation of the linear polarization plane of light during its propagation by an angle called the CB angle. Linearly polarized light is used to study this phenomenon and, due to the fact that the CB angle is very tiny as found by the most recent con- straints all compatible with a null value, the Cosmic Microwave Background (CMB), that is the oldest linearly polarized light we can detect, is a great case study for this effect. Several estimators based on the CMB power spectrum, altered by the CB effect, have been developed, among which are the so-called D estimators. The CB angle can be directly estimated by finding the angle that nulls the expectation value of the D estimators. It is possible to divide all the observable sky in small patches all with the same area and to estimate the CB angle with the D estimators in each of these patches. In a single patch the CB effect is assumed isotropic and the values of the angles in all the patches are then used to build the CB power spectrum. In this work, the resolu- tion of the patches has been improved with respect to past studies but, in order to do this, a high computational effort was needed. During this talk, after an introduction to the topics described above, a new paral- lel script used to estimate the CB angle on small patches of the sky will be presented. The program is fully written in Python and it is run on High Performance Comput- ing clusters. After validating the results with realistic simulations of the Planck CMB satellite experiment, that do not contain the CB effect, the Planck data files are ana- lyzed and the results are compared with the simulations. In addition to the CB angle estimates and its power spectrum, new cross-correlation between the CB and other cosmological fields are studied, like the E or B CMB modes or the lensing field of large scale structure in the Universe. Finally, new forecasts of the CB effect for forthcoming CMB experiments are obtained, e.g. for the LiteBIRD satellite.
Mon 10:50 am - 11:15 am

11:15 am - 11:45 am Break

No workshops in this session.

11:45 am - 12:10 pm Effect of Half-Wave Plate non-idealities on the estimate of cosmological parameters

Effect of Half-Wave Plate non-idealities on the estimate of cosmological parameters

Serena Giardiello

The Cosmic Microwave Background (CMB) radiation is a background light that became free to travel the Universe after the recombination of electrons and protons into hydrogen atoms, around 300000 years after the Big Bang. Before that event, photons were coupled to electrons through Compton scattering. As the Universe is not perfectly homogeneous but there were some (at that time) small perturbations sourced at very early times, Compton scattering in the presence of those inhomogeneities caused some amount of linear polarization of the CMB. We can distinguish between E-mode polarization, sourced by both scalar perturbations and tensor (Gravitational Waves) perturbations and B-modes, sourced only by tensor perturbations. Because of that, a signal from primordial B-modes would be an indication of a primordial GW background. The latter is a fundamental prediction of inflation, i.e. the mechanism we believe is at play at very early times. We parametrize the amplitude of primordial GW through the tensor-to-scalar ratio parameter, r. Future cosmological missions aim to detect the signal of primordial B-modes, which is much weaker than the E-mode one, and to constrain r. To that end, the systematic effects of the observatory/satellite have to be measured and calibrated with a very high accuracy. In this talk I will describe different non-idealities of an optical element that will be employed to extract the CMB polarization signal by several future telescopes, the Half-Wave Plate (HWP). The advantages of a rapidly spinning HWP are the decrease of the 1/f noise and of systematics associated with alternative methods of polarization extraction (pair-differencing of orthogonal detectors). Despite the benefits introduced by the HWP, its manufacturing imperfections could be a source of systematics, too. These non-idealities are formulated here in the Jones formalism, i.e. describing how they affect the electromagnetic field incident on the Plate. From that, it is straightforward to see how the total intensity and polarization of the incoming signal get modified. I will present a simulation of a couple of orthogonal detectors observing the sky with the scanning strategy of LiteBIRD, a future satellite whose primary goal is the detection of primordial B-modes. We simulate the effects of HWP non-idealities on the observation of the CMB sky. We also include the effect of foreground emissions from our galaxy, which in general spoil the measurement of the CMB signal on the galactic plane. In particular, we explore the effect of imperfect knowledge of systematic parameters, which, if perfectly measured, could be corrected for in the construction of a map from the observed signal. From the observed maps, we describe how errors in the measurement of the non-idealities propagate to the estimate of r. Setting a limit to the tolerable bias on r, we can derive requirements on the precision that future measurements of the HWP non-idealities should achieve.
Mon 11:45 am - 12:10 pm

12:10 pm - 12:35 pm CMB lensing and radio galaxy cross-correlation study

CMB lensing and radio galaxy cross-correlation study

Giulia Piccirilli

Given the upcoming release of wide galaxy surveys (e.g. Euclid and Rubin Observatory), the advent of future radio surveys like SKA, and the recent high sensitivity maps of the Cosmic Microwave Background (CMB) delivered by Planck, it is crucial and timely to investigate the interactions and complementarities of these diverse probes of the Large Scale Structure (LSS) of the Universe. Studying the cross-correlation of different observables, which are linked to the same physics, is a unique tool to maximise the outcome of each of them and to provide information otherwise inaccessible to each measurement alone. However, wide surveys are prone to systematic uncertainties when investigating large scale correlation properties and, as reported by previous studies, this seems especially true for radio surveys. “Anomalous” large scale power has been detected, for example, in the data of the NRAO VLA Sky Survey (NVSS) and the TIFR GMRT Sky Survey (TGSS). I will discuss how we exploit the cross-correlation analysis between two radio galaxy catalogues form these two surveys, and the lensing potential reconstructed from Planck CMB data to investigate the nature of the anomalous features. While propagating across the Universe, CMB photons experience gravitational lensing due to the dark matter distribution encountered along the trajectories. Therefore, the gravitational potential reconstructed from CMB lensing data is an integrated measure of all the matter in the Universe back to the Last Scattering Surface and it contains contributions from a huge range of intervening distances. According to gravitational instability theories, galaxies form in peaks of the cosmic density field and their distribution reflects the underlying dark matter structure which contributes to the lensing potential. Consequently, a meaningful correlation between CMB lensing potential and other tracers of the same LSS, as radio sources distribution, is expected to be found. We report a high significance detection of cross-correlation with CMB lensing for both NVSS and TGSS catalogues, obtaining a first measurement for the latter. I will explain how we interpret these results in the context of the ΛCDM cosmological model. In particular, we use two state-of-the-art simulations for characterizing the redshift distribution of radio sources (SKA Simulated Skies S 3 by Wilman et al. 2008 and the Tiered Radio Extragalactic Continuum Simulation by Bonaldi et al. 2018) and we explore several physically motivated models for galaxy bias. Finally, I will expose some possible future applications of cross-correlation between CMB lensing and galaxy distribution to give an insight on its importance for cosmological studies. For instance, it is possible to assess how the inclusion of the cross-correlation with CMB lensing can improve cosmological constraints with respect to standard analyses and how it is useful to derive novel constraints on the nature of the dark sector of the Universe.
Mon 12:10 pm - 12:35 pm

12:35 pm - 1:00 pm Updated cosmological constraints on Macroscopic Dark Matter

Updated cosmological constraints on Macroscopic Dark Matter

Luca Caloni

Cosmological observations suggest that roughly 26% of the energy content of our Universe consists of dark matter (DM), a yet unknown form of matter which manifests its presence through gravi- tational interaction. The DM played a crucial role in the evolution of the Universe, allowing the small density fluctuations present in the early Universe to grow and collapse, leading eventually to the wealth of structures (e.g., galaxies and galaxy clusters) that we observe today in the sky. However, despite knowing some basic properties of DM, its fundamental nature is still unknown and represents one of the major puzzles of both cosmology and particle physics. While there exist many theoretically motivated models which explain the dark matter as a new particle be- yond the Standard Model of particle physics, experimental evidence in laboratory searches is still lacking. It is thus important to keep an open mind on alternative scenarios, some of which could be realized within the Standard Model itself. An appealing possibility is that the dark matter consists of macroscopic-size objects, generically dubbed as Macroscopic Dark Matter (MDM) or Macros, which interact with ordinary matter predominantly via their large geometric cross-section. A possible signature of MDM is the capture of baryons from the cosmological plasma in the pre- recombination epoch, with the consequent injection of high-energy photons in the baryon-photon plasma. Without referring to any specific theoretical models, I will discuss the cosmological phe- nomenology of two distinct classes of Macros, composed either of ordinary matter or antimatter. In both scenarios, I wll also analyze the impact of a non-vanishing electric charge carried by Macros. I will focus on the following probes of MDM: the change in the baryon density between the end of the Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB) decoupling, the production of spectral distortions in the CMB and the kinetic coupling between charged MDM and baryons at the time of recombination. While discussing these results, I will also show that future CMB spectral distortions experiments, like PIXIE and SuperPIXIE, would have the sensi- tivity to probe larger regions of the Macro parameter space: this would allow either for a possible evidence or for an improvement of the current bounds on Macros as dark matter candidates.
Mon 12:35 pm - 1:00 pm

1:00 pm - 1:25 pm Sar-Grav Laboratory and the third generation of gravitational waves detectors

Sar-Grav Laboratory and the third generation of gravitational waves detectors

Iara Tosta e Melo

Gravitational waves (GWs) detectors, measure tiny changes in the lengths of two connected arms several kilometers long, caused by a passing GW. The first and second generations of these interferometric detectors constrained the GW emission from several sources and have made the first direct detection of GWs. However, these detectors will not be sensitive enough for very precise astronomical studies of the GW sources, and new detector sites are required. The Einstein Telescope (ET) is a design concept for a European third-generation GW detector, which will be 10 times more sensitive than the current advanced instruments. The surroundings of Sos Enattos mine in Sardinia is being considered as a possible location for ET due to its very low seismic and anthropogenic noise. Such local characteristics allowed the construction of the Sar-Grav laboratory which aims to host underground experiments including low seismic noise experiments, cryogenic payloads, low frequency, and cryogenic sensor development. Nonetheless, a fundamental physics experiment, Archimedes, is the first experiment already under installation in the surface area.
Mon 1:00 pm - 1:25 pm

1:25 pm - 1:30 pm Final greetings

No workshops in this session.

Tuesday 7 Sep 2021

9:00 am - 1:05 pm Day 2 – Morning session

9:00 am - 10:00 am Invited speaker

A scientific experience somewhere between engineering and physics (and between Italy and Germany)

Chiara Gianoli

Chiara Gianoli has been working at the department of medical and experimental physics at Ludwig- Maximilians-Universität München (Ludwig Maximilian University of Munich) since 2014. He studied at the Politecnico di Milano and received his European Ph.D. degree in 2013 in collaboration with the Universitätsklinikum Heidelberg (university hospital of the University Ruperto Carola in Heidelberg) and the Heidelberg Ion Beam Therapy Center (HIT). Since 2017 Chiara is principal investigator of a project on imaging in cancer radiotherapy using ions (protons, helium and carbon ions). She has recently embarked on the academic path to obtain the qualification of Habilitation. Chiara is the mom of Margherita and Mathilde, 3.5 and 1.3 years old, respectively.
Tue 9:00 am - 10:00 am

10:00 am - 10:25 am Modelling swift charged particles interaction with biologically-relevant materials for a deeper understanding of ion-beam radiation biodamage

Modelling swift charged particles interaction with biologically-relevant materials for a deeper understanding of ion-beam radiation biodamage

Pablo de Vera

An accurate modelling of swift charged particles (ions and their secondary electrons) interaction with biomaterials, and with other relevant targets such as radiosensitisers, is necessary for a better understanding (and possibly improvement) of proton- and hadrontherapy [1, 2]. This modality of radiotherapy, available in Trento since 2014, features a dose distribution and tumour cell killing probability superior to the conventionally used X-rays, due to the characteristic physico-chemical interactions initiated in the medium by the swift ions. The latter span over different space, time and energy scales, making their study challenging [1]: while the propagation of the primary ion beam happens on the macroscopic scale, the main processes behind clustered DNA damage and cell death (electronic excitations, generation and transport of large numbers of secondary electrons and free radicals, etc.) occur on nanometre distances around ion tracks. Thus, a detailed simulation of this chain of processes underlying ion-beam biodamage requires the combination of different computational techniques. Monte Carlo simulations are very effective tools for describing ion and secondary electron transport in condensed matter [3, 4], but their accuracy strongly depends on the quality of the interaction probabilities (cross sections) with which they are fed. The dielectric response theory, together with time- dependent density functional theory, are versatile and reliable methods for calculating the electronic excitation and ionisation cross sections, including the description of the energy and angular distributions of secondary electrons [5, 6], as well as the treatment of very low energy electron transport [7]. At the atomistic level, biomolecular damage can be dealt with by classical and reactive molecular dynamics simulations [8]. The combination of these methodologies becomes especially important for the fundamental study of newly explored treatment modalities heavily relying on nanoscale phenomena, such as the use of nanoparticles as enhancers of hadrontherapy, whose working mechanisms are still not well understood [2]. In the present contribution, the above mentioned methods will be reviewed, with examples of their application to the study of different aspects of the problem. References [1] A. V. Solov’yov (ed.) Nanoscale Insights into Ion-Beam Cancer Therapy (Springer, 2017) [2] S. Lacombe, E. Porcel, E. Scifoni, Cancer Nanotechnology 7 (2016) 8 [3] P. de Vera, I. Abril, R. Garcia-Molina, Radiation Research 180 (2018) 282 [4] M. Dapor, Transport of Energetic Electrons in Solids. Computer Simulation with Applications to Materials Analysis and Characterization, 3rd ed (Springer, 2020) [5] P. de Vera, R. Garcia-Molina, I. Abril, Physical Review Letters 114 (2015) 018101 [6] S. Taioli, P. E. Trevisanutto, P. de Vera, S. Simonucci, I. Abril, R. Garcia-Molina, M. Dapor, Journal of Physical Chemistry Letters 12 (2021) 487 [7] P de Vera I. Abril, R Garcia-Molina, Physical Chemistry Chemical Physics 23 (2021) 5079 [8] P. de Vera, E. Surdutovich, A. V. Solov’yov, Cancer Nanotechnology 10 (2019) 5
Tue 10:00 am - 10:25 am

10:50 am - 11:15 am Understanding long-range near-side ridge correlations in p−p collisions using rope hadronization at LHC energies

Understanding long-range near-side ridge correlations in p−p collisions using rope hadronization at LHC energies

Pritam Chakraborty

The observation of long range ridge-like structure in the near-side region of the two particle ∆η − ∆φ correlations as measured by CMS and ATLAS experiments at LHC in high multiplicity p−p collisions at √ s = 7 TeV and 13 TeV indicated towards the presence of collectivity in the small system which are similar to that observed in p−A(nucleon-nucleus) and A−A (nucleus-nucleus) collisions. The particle production in high multiplicity events in hadronic collisions are highly influenced by non-perturbative QCD processes and the study of such events can provide information about the potential microscopic processes leading to such novel observations. In this work, the two particle correlation between the charged particles in ∆η − ∆φ for p−p collisions at √ s = 7 TeV and 13 TeV is studied using Pythia 8 event generator within the framework of different final-state partonic color reconnection effects such as multi-partonic interactions (CR-0), QCD mode (CR-1) and the gluon-move scheme (CR-2) etc. as well as the microscopic rope hadronization model. The rope hadronization relies on the formation of ropes due to overlapping of strings in high multiplicity events followed by string shoving. A correlation peak near (∆η, ∆φ) = (0, 0), originated primarily due to jet fragmentation and an away side (∆φ ∼ π) ridge-like structure extended up to higher values of |∆η| containing the contributions from back-to-back jets are observed for both low and high multiplicity events for both the energies. Also, ridge-like structures at near side have also been observed for high-multiplicity events for both the energies when the mechanism of rope hadronization (with shoving) was enabled, which is qualitatively similar to the observed ridge in data. The observed two-dimensional correlation functions were projected into one-dimensional distribution in ∆φ for different ∆η ranges, namely the short range (when projected over ∆η < 1.0, the jet region) and the long range (∆η > 2.0, the ridge region). In the long range region, along with the away-side peaks emanating from back-to-back jets for all the three multiplicity classes, non-zero associated yield peaks in the near side are also observed in the near-side for long-range region for high multiplicity events when the rope hadronisation is enabled. Both the near-side and away-side peaks are observed in the short range region which are originated from the jets and away-side ridge like structure, respectively. The strength of the correlation function is higher for CR-1 and CR-2 mode compared to CR-0 mode. The observed ridge-like structure in the near-side region is qualitatively similar to the ones observed in data which supports the idea that microscopic processes at partonic level can mimic collectivity like features without assuming the formation of a thermalised medium.
Tue 10:50 am - 11:15 am

11:15 am - 11:45 am Break

No workshops in this session.

11:45 am - 12:10 pm The stochastic nature of the near-Sun solar wind turbulence

The stochastic nature of the near-Sun solar wind turbulence

Tommaso Alberti

The solar wind has been shown to be a natural laboratory for plasma physics, covering a wide range of scales and being characterized by a large variety of phenomena as turbulence and intermittency. A lot of attention has been directed towards understanding the scale-invariant features and self- organization of both the MHD/inertial and the kinetic/dissipative regimes, providing evidence of both direct and inverse energy/enstrophy cascade mechanisms. When exploring the multiscale variability of solar wind parameters, these approaches are not able to investigate scale-to-scale effects, only providing a global view of the system over a specific range of scales. One of the most intensively studied contemporary problems in nonlinear sciences is the characterization of the multiscale nature of fluctuations in systems showing signatures of chaos and recurring large-scale patterns. All these features point towards the existence of an underlying attractor. Its properties have long been investigated within dynamical systems theory often with little success: many natural systems usually show different scaling regimes with different physical and dynamical properties. These features made practically impossible to get a clear picture of the attracting set. In this talk we apply a novel formalism to characterize the instantaneous scale-dependent phase- space topology of solar wind magnetic field fluctuations from sub-proton to the inertial scales. By using high time-resolution measurements collected by the Parker Solar Probe mission near the first perihelion via two instruments on the FIELDS suite we show that large-scale intermittent-like variations cannot be definitely associated with coherent intermittent events belonging to the MHD domain, but seem to be related to an underlying stochastic strange attractor at sub-proton scales, in close analogy with the results obtained for fluid turbulence. This is in agreement with recent findings obtained with PSP measurements on the non-Gaussian scaling nature of the sub-proton range suggesting the existence of a scale-invariant population of current sheets between ion and electron inertial scales.
Tue 11:45 am - 12:10 pm

12:10 pm - 12:35 pm Correlation analysis for time series with similar periods: the solar activity-solar wind case

Correlation analysis for time series with similar periods: the solar activity-solar wind case

Raffaele Reda

Assessing the relationship between time series is a topic to often deal with in many fields of physics, but not only. Depending on the intrinsic properties of the signals this task can be more or less complicated, or even not possible in some cases. Here we present a technique to search for correlation in time series with quite similar periodicities. It has been used to evaluate the long term behaviour of the solar wind and to understand the nature of its relationship with solar activity cycles. To this scope we used data of a physical proxy of the solar magnetic activity, the Ca II K index, and solar wind OMNI parameters for the time interval between 1965 and 2021, which covers the last 5 solar cycles almost entirely. We found a time lag in the correlation between the parameters, that seems to show a temporal evolution over the different solar cycles. Furthermore, we found that these time series are characterized by similar, but not equal, main periods which lead to phase asynchrony over the time and make difficult to point out the existence of a relationship between the signals. By taking them into account we show how a correlation relation emerges, which appears to be valid for the whole time interval. The results from this analysis offer the possibility to deepen the understanding of the process that link the global dynamo to solar variability and to the properties of the near-Earth solar wind. Moreover, the use of a physical proxy to quantify the solar variability has the advantage that the relations found for the Sun can be easily extended to other stars for which similar measurements are available. This makes it possible to link stellar activity to stellar wind properties, to evaluate the stellar activity effects on the exoplanetary environment.
Tue 12:10 pm - 12:35 pm

12:35 pm - 1:00 pm Investigation of the Physical Processes Involved in GNSS Amplitude Scintillations at High Latitude: A Case Study

Investigation of the Physical Processes Involved in GNSS Amplitude Scintillations at High Latitude: A Case Study

Giulia D'Angelo

The storm onset on September 7, 2017, triggered several variations in the ionospheric electron density, causing severe phase fluctuations at polar latitudes in both hemispheres. In addition, although quite rare at high latitudes, clear amplitude scintillations were recorded by two Global Navigation Satellite System receivers during the main phase of the storm. This work attempted to investigate the physical mechanisms triggering the observed amplitude scintillations, with the aim of identifying the conditions favoring such events. We investigated the ionospheric background and other conditions that prevailed when the irregularities formed and moved, following a multi-observations approach. Specifically, we combined information from scintillation parameters recorded by multi-constellation (GPS, GLONASS and Galileo) receivers located at Concordia station (75.10°S, 123.35°E) and SANAE IV base (71.67°S, 2.84°W), with measurements acquired by the Special Sensor Ultraviolet Spectrographic Imager on board the Defense Meteorological Satellite Program satellites, the Super Dual Auroral Radar Network, the Swarm constellation and ground-based magnetometers. Besides confirming the high degree of complexity of the ionospheric dynamics, our multi-instrument observation identified the physical conditions that likely favor the occurrence of amplitude scintillations at high latitudes. Results suggest that the necessary conditions for the observation of this type of scintillation in high-latitude regions are high levels of ionization and a strong variability of plasma dynamics. Both of these conditions are typically featured during high solar activity.
Tue 12:35 pm - 1:00 pm

1:00 pm - 1:05 pm Final greetings

No workshops in this session.

2:30 pm - 7:30 pm Day 2 – Afternoon session

2:30 pm - 3:30 pm Lectio Magistralis

Space exploration: status and perspectives

Roberto Battiston

A review of the challenges which space travel will be facing during missions to Moon, Mars and to other remote destinations Roberto Battiston is the former President of the Italian Space Agency (ASI) and a member of CEPR, the governmental committee advising the Minister of Research and Universities. He has worked for over 30 years in international collaborations in the field of experimental physics and fundamental interactions: Strong interactions, Electroweak interaction physics, Search for antimatter and dark matter in Cosmic Rays. He is also the founder of a research group in Perugia working in the field of frontier detectors and technologies to be used in fundamental physics research – ground based and space based. In 1994 he founded SERMS (Laboratory for the Study of the Effects of the Radiation on Special Materials), devoted to the characterization of materials and devices to be used in space conditions. He is also the Deputy spokesperson for the AMS experiment, the first fundamental physics experiment approved on the International Space Station, already successfully flown during the STS91 Shuttle flight in june 1998 and installed on the ISS in 2011. Prof. Battiston is the Italian PI for the LIMADOU, to develop and energetic particle payload for the Chinese CSES satellite, and the Coordinator of the SR2S EU project (2013 – 15) to develop active shielding techniques for interplanetary flights. Author of more than 420 papers published on international scientific journals, and organizer of several workshops devoted to space science and to advanced technologies (Trento 1999, Elba 2002, Washington 2003, Bejijng 2006, CERN 2012). He graduated at Scuola Normale of Pisa (1979) and possess a Doctorate (Troisième Cycle), University of Paris IX, Orsay, 1982. He has been the Chair of General Physics at the Engineering Faculty of the Perugia University, Faculty of Engineering, (1992 – 2012). He is now the Chair of General Physics at the Physics Department or the Trento University. He received a Laurea honoris causa from the Universtiy of Bucharest (2000)
Tue 2:30 pm - 3:30 pm

3:30 pm - 7:30 pm Poster session

Detailed plan to be defined

Tue 3:30 pm - 7:30 pm

Wednesday 8 Sep 2021

9:00 am - 12:30 pm Day 3 - Morning session

9:00 am - 10:00 am Invited Speaker

What is the Spectrum of Hadrons?

Alessandro Pilloni

Alessandro Pilloni is a tenure-track professor at Messina University. He has completed his Ph.D. in theoretical particle physics at the “Sapienza” University in Rome, Italy, where he was born and raised. After that, he held postdoctoral positions at Jefferson Lab (Virginia, USA), at ECT* (Trento, Italy), and as a FELLINI (Marie Skłodowska-Curie Cofund) at INFN Roma. His research interests range to several aspects of Quantum Chromodynamics, and in particular of the Spectroscopy of Hadrons. Most of his work is realized in close connection with experiments. He is also a member of the BaBar collaboration and affiliated theorist to the LHCb collaboration.
DocumentsSlides (29 MB)
Wed 9:00 am - 10:00 am

10:00 am - 10:25 am Quantum gravitational decoherence from minimal length

Quantum gravitational decoherence from minimal length

Luciano Petruzziello

Following early pioneering studies, the investigation of the quantum-to-classical transition via the mechanism of decoherence has become a very active area of research, both experimentally and theoretically, playing an increasingly central role in the research area on the foundations of quantum mechanics and the appearance of a classical world at the macroscopic scale. Schemes of gravitationally induced decoherence are being actively investigated as possible mechanisms for the quantum-to-classical transition. In this talk, I introduce a decoherence process attributable to quantum gravitational effects. In particular, I assume a foamy quantum spacetime with a fluctuating minimal length coinciding on average with the Planck scale. This approach clearly draws inspiration from quantum gravity. Actually, it must be said that a complete and consistent theory of quantum gravity is still lacking, but all the different current candidates including string theory, loop quantum gravity, non-commutative geometry and doubly special relativity, predict the existence of a minimal length at the Planck scale. An immediate consequence of this common aspect is the breakdown of the Heisenberg uncertainty principle (HUP), whose most famous formulation conveys that spatial resolution can be made arbitrarily small with a proper energetic probe. Considering deformed canonical commutation relations from which the generalized version of HUP can be derived, it is possible to achieve a master equation of the Lindblad-Gorini-Kossakowski-Sudarshan form for the averaged quantum density matrix out of the corresponding deformed Schr ̈odinger equation for the quantum state vector, and one can study the physical consequences of such open quantum state dynamics. Such a proposal may be regarded as a possible universal decoherence mechanism. Compared to other schemes of gravitational decoherence, one can see that the decoherence rate predicted by this model is extremal, being minimal in the deep quantum regime below the Planck scale and maximal in the mesoscopic regime beyond it. Finally, I briefly discuss possible experimental tests of the model based on cavity optomechanics setups with ultracold massive molecular oscillators and provide preliminary estimates on the values of the physical parameters needed for actual laboratory implementations.
Wed 10:00 am - 10:25 am

10:25 am - 10:50 am Resolution of the non-locality problem in the Aharonov-Bohm effect

Resolution of the non-locality problem in the Aharonov-Bohm effect

Kolahal Bhattacharya

The Aharonov-Bohm effect shows that charged particles can be affected by the potentials in the regions where there is no classical field. This observation led to the concept of non-local interaction in quantum mechanics. In a recent paper [1], the issue has been resolved by developing a semi- classical model of the classical fields. It has been shown that the wave amplitudes of these fields can exist even if the classical field is zero and this leads to the observation in case of the Aharonov- Bohm effect. In this presentation, I will discuss the work and will explain why it has been difficult to experimentally observe the electrostatic Aharonov-Bohm effect. I will also argue that this work leads to the concept of quantisation of electric charge and magnetic flux. 1. Kolahal Bhattacharya “Demystifying the nonlocality problem in Aharonov-Bohm effect”. - accepted in Physica Scripta (IOP Publishing); DOI: 10.1088/0031-8949/91/3/035501, Vol 96 Number 8: pp. 11, 2021.
Wed 10:25 am - 10:50 am

10:50 am - 11:20 am Break

No workshops in this session.

11:20 am - 11:45 am Impurity dephasing in a Bose-Hubbard model

Impurity dephasing in a Bose-Hubbard model

Fabio Caleffi

We study the dynamics of a two-level impurity embedded in a two-dimensional Bose-Hubbard (BH) model at zero temperature from an open quantum system perspective. Results for the decoherence dynamics of the impurity across the whole phase diagram are presented, with a focus on the critical region close to the Mott-superfluid transition. In particular, we show how the decoherence and its deviation from a Markovian behaviour are sensitive to whether the phase transition is crossed at commensurate or incommensurate densities. The role of the spectrum of the BH environment and its non-Gaussian statistics, beyond the standard independent boson model, is highlighted. Our analysis resorts on a recently developed method [1] - closely related to slave boson approaches - that enables us to capture quantum correlations across the BH phases and provides deep insights into the physics of pure dephasing from the point of view of the many-body excitations of the environment. References [1] - F. Caleffi, M. Capone, C. Menotti, I. Carusotto and A. Recati, Quantum fluctuations beyond the Gutzwiller approximation in the Bose-Hubbard model, Phys. Rev. Res. 2, 033276 (2020) [2] - F. Caleffi, M. Capone, I. de Vega and A. Recati, Impurity dephasing in a Bose-Hubbard model, New J. Phys. 23, 033018 (2021)
Wed 11:20 am - 11:45 am

11:45 am - 12:10 pm Switching Times of Josephson Junctions for Single Photons Detection

Switching Times of Josephson Junctions for Single Photons Detection

Alex Stephane Piedjou Komnang

In the past two decades, the development of nanotechnologies and superconducting materials has led to the possibility to design ultrasensitive sensors for very weak signals, even close to the quantum limit. Among the superconducting elements, Josephson junctions (JJs) stand as a promising candidate to detect weak microwave signals, or even single microwave photons. The detection in this range of frequencies, that is below the terahertz band, is challenging, for the energy of a photon is comparable to thermal energy. JJs are promising for they operate in the range of microwave region and being superconducting elements can be cooled as much as cryogenics allow[1, 2]. In a suitable configuration for photon detection, a JJ is exposed to a microwave field that induces the appearance of a voltage, as the perturbation induces a switch from the superconducting to the resistive state. In this set-up, the confounding thermal-induced transitions are to be kept at bay lowering the operating temperature, for they produce spurious events that corrupt the detection process. In this talk we show how to carefully plan Josephson-based experiments devised to decide about the existence of a weak electromagnetic signal in a thermal noise background, and to achieve the best conditions to reveal the photon field in the frame of signal detection [3, 4]. The analysis considers a JJ prepared in the superconducting state, and proposes to collect the waiting times of the device prior to a switch towards the finite voltage state [5, 6]. The employed methodology consists in comparing the switching probabilities of a junction exposed to a train of current pulses, which mimics a weak photon field, with that of the same device in absence of pulses. The investigation of the unbalance in the number of switching events in the two cases, gives an estimate of the efficiency of the detection. The optimization of the detection probability will give a guide to select the JJ parameters that best suit to reveal weak microwave signals. 1. Alesini, D., et al., “Status of the simp project: Toward the single microwave photon detection”, Journal of Low Temperature Physics 199, 348 (2020). 2. Alesini, D., et al., “Development of a Josephson junction based single photon microwave detector for axion detection experiments”, Journal of Physics: Conference Series 1559, 012020 (2020). 3. Filatrella, G. and Pierro, V. “Detection of noise-corrupted sinusoidal signals with Josephson junctions”, Phys. Rev. E, 82, 0467121-9 (2010) 4. Addesso, P., et al. “Characterization of escape times of Josephson junctions for signal detection”, Phys. Rev. E, 85, 016708 (2012) 5. Piedjou Komnang, A., et al. “Analysis of Josephson junctions switching time distributions for the detection of single microwave photons”, Chaos Solitons Fract 142, 110496 (2021) 6. Filatrella, G., et al. “Analysis of thermal and quantum escape times of Josephson junctions for signal detection” in publications in 13th Chaotic Modeling and Simulation International Conference (2021)
Wed 11:45 am - 12:10 pm

12:10 pm - 12:35 pm Engineering the Dispersion Relation in Josephson Traveling Wave Parametric Amplifiers

Engineering the Dispersion Relation in Josephson Traveling Wave Parametric Amplifiers

Angelo Greco

Circuit Quantum Electrodynamics applications such as microwave superconducting-based Traveling Wave Parametric Amplifiers (TWPA) are expected to bring many advantages to a wide range of scientific fields and industries by offering functionality unattainable by their classical counterparts like a quantum-limited added noise. The paths followed in this direction mainly exploit two different technologies to give the non-linear nature to these devices: nonlinearity given by the kinetic inductance of superconductors and nonlinearity given by Josephson junctions (JJs). Both these approaches have advantages and disadvantages, kinetic inductance based TWPA have shown high gain and near quantum-limited added noise but require high pump tones and bias currents in cryogenic environments to work properly, making their integration challenging in very extended setups. On the other hand, JJs based TWPA (JTWPA) can work with much lower DC and microwave powers thanks to the high nonlinear inductance that characterise JJs, but the spread in the critical currents, which in principle should all be identical, imposes severe constraints on the performance of this technology since the average number of JJs required for these devices to work is in the order of 1000. In addition, both families of devices suffer from a high power conversion in higher unwanted harmonics, a fact that can be detrimental for an efficient amplification since it prevents the energy to be transmitted to the signal of interest. A feasible solution to this issue is to lower the cutoff and plasma frequencies of the transmission lines, resulting in an attenuation of these higher harmonics and a phase mismatch between them, so that the parametric conversion effect cannot take place. Nonetheless, in order to avoid phase mismatch among the signals that we actually want to amplify, a rephasing technique needs to be introduced. Rephasing is possible by modifying the dispersion relation of the nonlinear medium, for example through the so-called Resonant Phase Matching (RPM) technique, which consists of periodically placing shunt resonators between the line and the ground that open a stop band in the dispersion relation, or the Quasi-Phase Matching (QPM) technique, which is based on poling the sign of the leading nonlinear coefficient of the medium, unlocking phase matching through all the device. In this work we present cryogenic microwave characterisations of JTWPAs equipped with RPM and QPM, measuring the gain, bandwidth and added noise. We also present a quantum model which theoretically explains the behaviour of JTWPAs in presence of single-photon signals.
Wed 12:10 pm - 12:35 pm

12:35 pm - 12:40 pm Final greetings

No workshops in this session.

Thursday 9 Sep 2021

9:00 am - 1:30 pm Day 4 - Morning session

9:00 am - 10:00 am Invited speaker

Transient exposure of a buried phosphorylation site in an autoinhibited protein

Simone Orioli

Autoinhibition is a mechanism used to regulate protein function, often by making functional sites inaccessible through the interaction with a cis-acting inhibitory domain. Such autoinhibitory domains often display a substantial degree of structural disorder when unbound, and only become structured in the inhibited state. These structural dynamics make it difficult to study the structural origin of regulation, including the effects of regulatory post-translational modifications. In this talk, I will show our study of the autoinhibition of the Dbl Homology domain in the protein Vav1 by the so-called acidic inhibitory domain. We used molecular simulations to study the process by which a mostly unstructured inhibitory domain folds upon binding and how transient exposure of a key buried tyrosine residue makes it accessible for phosphorylation. We show that the inhibitory domain, which forms a helix in the bound and inhibited stated, samples helical structures already before binding and that binding occurs via a molten-globule-like intermediate state. Together, our results shed light on key interactions that enable the inhibitory domain to sample a finely-tuned equilibrium between an inhibited and a kinaseaccessible state.
Thu 9:00 am - 10:00 am

10:00 am - 10:25 am Innovative polymer-carbon nanotube based conducting devices

Innovative polymer-carbon nanotube based conducting devices

Anna Prioriello

In the last few decades we have seen the increasing request, emergence and application of composite materials with suitable electrical, elasto-plastic and mechanical properties useful in various industrial and research fields. In particular we have witnessed a growing combination of polymeric substrates with Carbon Nanotubes (CNT); this coupling is highly developed thanks to the interesting mechanical, optical and electrical CNT properties. For this reason, CNT, both single walled and multi walled, have been used in many applications and they have been introduced in the medical context, too. Our purpose is improving innovative biomedical composites based on polymers and CNT [1] for the manufacture of stretchable and flexible electrodes capable of both recording electrical signals (e.g. neuronal or muscular) and stimulating the region of interest, while being fully biocompatible. In this work, we investigate the physical processes that allow the CNT grafting on the polymeric substrate, in absence of chemical functionalization of the nanotubes. Starting from Molecular Dynamics simulations, focused on how different polymeric chains interact with single or bundled CNT and the dispersion of CNT in water, we are investigating the following crucial points of the grafting mechanism: 1. The role of the disentanglement of the CNT bundles; 2. The role of temperatures near the polymer melting point in the minimization of the interaction energy; 3. The role of the concentration of the surfactant used to prepare the CNT suspensions, both on the CNT unravelling and on the grafting mechanism. Thanks to these simulations, we obtain valuable evidences that allow us to improve the realization of these multi-functional composites. Moreover, the results allow us to optimize the preparation procedure making it more reliable and to obtain reproducible electrical and mechanical properties of the electrodes. Moreover, these devices have already been implanted in model rats with the aim of monitoring the spike-wave discharges in rats spontaneously developing absence epilepsy. Since we are interested in chronic implantation of such devices, also in human subjects, we want to demonstrate that they are not a constrain for the medical investigation. For this reason we have carried out Magnetic Resonance Imaging experiments to prove the compatibility of these devices with such procedure and hence the possibility of a their chronic implant. Keywords: Polyethylene, Carbon Nanotubes, Biomedical Composites, Molecular Dynamics, Multi-functional Composites [1] Fazi, L., Prioriello, A., Scacco, V., Ciccognani, W., Serra, E., Gattia, D. M., ... & Senesi, R. (2020, May). Stretchable conductors made of single wall carbon nanotubes self-grafted on polymer films. In Journal of Physics: Conference Series (Vol. 1548, No. 1, p. 012023). IOP Publishing.
Thu 10:00 am - 10:25 am

10:25 am - 10:50 am F(β) analysis method for β-PVDF thin films

F(β) analysis method for β-PVDF thin films

Valerio Scacco

Polyvinylidene fluoride (PVDF) shows piezoelectric effects that can be engaging for electroactive composite. PVDF occurs in several phases, with the β phase showing piezoelectric effects. Starting from the polymer powder it is possible to manufacture thin films whose properties are strongly affected by temperature and rotational speed of the deposition surface in the spin coating procedure. The aim of this work is providing a reliable method for measuring the F(β) function that is related to the percentage of β phase in the PVDF from the analysis of ATR-FTIR spectra (more specifically, from the intensity of the infrared characteristic peaks of the β and α phases of the polymer, at 840cm−1 and 760cm−1 , respectively). We manufactured several thin films of PVDF, varying the aforementioned parameters; after that we used a attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrometer to measure the spectrum of molecular vibrations, through which the intensity values of the two peaks α and β are obtained. By a multiparametric analysis, we can calculate the respective contributions through which we obtain the values of F(β) as a function of the deposition temperature and the rotation rate, for different concentrations of PVDF powder in solution. We then found a way to improve the manufacturing method of thin films, to maximize the percentage of β phase in the polymer, i.e. its piezoelectric effects. Moreover, a scanning electron microscope (SEM) characterization has been performed on such films, allowing to distinguish the amount of β phase in terms of characteristic features in the surface morphology of polymeric samples on a micrometric scale. Since the purpose of the research is obtaining electroactive and multi-functional composites, single-walled carbon nanotubes (SWCNT) have been grafted on the β-PVDF surface. Again, the morphology of such materials have been characterized by SEM analysis. This kind of composites can be used in sensory (e.g. smart clothing) and biomedical fields, thanks to the biocompatibility of the polymer. Keywords: Polyvinylidene fluoride, ATR-FTIR, Multi-functional composite, Spectral analysis, Single-walled carbon nanotubes, SEM.
Thu 10:25 am - 10:50 am

10:50 am - 11:20 am Break

No workshops in this session.

11:20 am - 11:45 am Numerical Simulation of Combined Forced and Natural Convection in an Inclined Multi-Ventilated Cavity Filled with Nanofluids

Numerical Simulation of Combined Forced and Natural Convection in an Inclined Multi-Ventilated Cavity Filled with Nanofluids

Ismail Arroub

Mixed convection (forced and natural convection combination) in vented cavities is widely encountered in many engineering applications, including cooling of electronic systems, heat exchangers, combustion chamber and solar energy systems. As is well known, conventional heat transfer fluids such as water, ethylene glycol and oil play important roles in many industrial applications, but their low thermal conductivities constitute the main drawback in enhancing the performance and the compactness of many engineering devices. One of the ways to overcome this problem is to add some solid nanoparticles with high thermal conductivity into the base fluid; the resulting fluid is called “nanofluid”. This may lead to an increase of the thermal conductivity of the obtained nanofluid and a substantial enhance of its heat transfer characteristics. In this study, the characteristic of flow and heat transfer of Al2O3-water nanofluids flowing through a tilted ventilated cavity is investigated numerically. The bottom wall is subjected to a constant temperature profiles, whereas the other boundaries are assumed to be thermally insulated. The enclosure is cooled by an injected or sucked imposed flow. The simulations focus specifically on the effects of different key parameters such as nanoparticles concentration, 0    0.05, and inclination angle, 0°    90°, on the flow and thermal patterns and heat transfer performances. The obtained results show that the presence of nanoparticles increases the heat transfer and the mean temperature within the cavity. On the other hand, an enhancement of heat transfer rate was achieved by increasing . Also, a better cooling of the cavity is reached with the suction mode since it leads to lower values of the mean temperature in comparison with the injection mode.
Thu 11:20 am - 11:45 am

11:45 am - 12:10 pm Effect of thermal radiation on mixed convection of Non-Newtonian Fluids with Temperature-Dependent Viscosity in lid-driven square cavity

Effect of thermal radiation on mixed convection of Non-Newtonian Fluids with Temperature-Dependent Viscosity in lid-driven square cavity

Ilham Erritali

The numerical study of fluid circulation and heat transfer by mixed convection in a lid-driven cavity present a major problem of engineering importance. The industrial relevance of such systems can be found in a variety of thermal engineering applications, such as cooling of electronic devices furnaces, lubrication technologies, high-performance building insulation, food processing, glass production, solar power collectors, drying technologies, indoor ventilation with radiators, microelectronics, nuclear reactors, solar power, drying, chemical process industries and others. As well as, the most of the fluids used or needed in various industrial and domestic applications are of the non-Newtonian type. Therefore, the main purpose of this numerical work is to study mixed convective heat transfer and non-Newtonian thermo-dependent fluids flow in lid-driven square cavity combined with thermal radiation effect. Where the cavity is heated uniformly from the left wall and cooled from the right side while insulated from horizontal walls, the upper wall is moving in the direction along x-axis. The simulations focus on the effects of various controlling parameters, such as Richardson number ( Ri = 0.1, 1 and 10), radiation parameter (Rd = 0–10), and the Pearson number (0 ≤ m ≤ 6) for a constant Grashof number of 104 and Prandtl number (Pr =7). The obtained results show that a growth of Richardson number decrease the heat transfer and convective flow attenuation. Also, an increase in the radiation parameter leads to a domination of conductive heat transfer for the fluid with high effective thermal conductivity. Finally, the growth of Pearson number increase the average Nusselt number and convective flow rate. Keywords – Numerical study, mixed convection, thermo-dependent viscosity, Thermal radiation, lid-driven Square cavity.
Thu 11:45 am - 12:10 pm

12:10 pm - 12:35 pm LBM simulations of mixed convection in lid- Driven cavity with discretely heated and cooled Side walls

LBM simulations of mixed convection in lid- Driven cavity with discretely heated and cooled Side walls

Daiz Abdelhak

A numerical investigation of mixed convection fluid flow and heat transfer in a discretely heated and cooled square lid-driven cavity has been carried out. The fluid in the cavity is a water-based nanofluid containing Al2O3 nanoparticles. The flow is induced by a shear force resulting from the motion of the top wall combined with buoyancy force due to the temperature differences. The top and bottom horizontal walls are assumed to be adiabatic while the right and left vertical walls are discretely heated/ cooled by imposed temperature TH/TC, with the top wall moving at a constant speed. The flow is assumed to be laminar and bidimensional. The work is motivated by the practical applications of such problem in many industrial transport processes and engineering devices, such as chemical vapor deposition instruments and cooling of microprocessors and electronic components. The governing equations modeling the problem are solved numerically by using Lattice Boltzmann Method with Single Relaxation Time (LBM-SRT). A computer code was developed with the D2Q9 model for the velocity and temperature fields to determine the whole structure of the flow. Comparisons with previously published works are performed and found to be in excellent agreement. The simulations were executed for various controlling parameters, such as Rayleigh number being fixed at 104 or 106 , Reynolds number ranging from 100 to 1000, and the solid volume fraction of nanoparticles varying from 0 to 0.07. The findings show that the presence of nanoparticles increases the heat transfer and the mean temperature within the cavity. In addition, the heat transfer rate depends on the heating or cooling position.
Thu 12:10 pm - 12:35 pm

12:35 pm - 1:00 pm Final greetings

No workshops in this session.