QUANTUM MACHINE LEARNING @ QuDIT:
methods traditionally developed for classical and quantum complex systems will be applied to optimize and characterize complex quantum computing machines and complex topological quantum states possibly establishing a relation between quantum computational complexity and quantum complex behavior.
We use a neural network variational ansatz to compute Gaussian quantum discrete solitons in an array of waveguides described by the quantum discrete nonlinear Schroedinger equation. By training the quantum machine learning model in the phase space, we find different quantum soliton solutions varying the number of particles and interaction strength. The use of Gaussian states enables measuring the degree of entanglement and the boson sampling patterns. We compute the probability of generating different particle pairs when varying the soliton features and unveil that bound states of discrete solitons emit correlated pairs of photons. These results may have a role in boson sampling experiments with nonlinear systems and in developing quantum processors to generate entangled many-photon nonlinear states.
Claudio Conti, arxv:2110.12379 (2021)
Training Gaussian boson sampling by quantum machine learning
We use neural networks to represent the characteristic function of many-body Gaussian states in the quantum phase space. By a pullback mechanism, we model transformations due to unitary operators as linear layers that can be cascaded to simulate complex multi-particle processes. We use the layered neural networks for non-classical light propagation in random interferometers, and compute boson pattern probabilities by automatic differentiation. This is a viable strategy for training Gaussian boson sampling. We demonstrate that multi-particle events in Gaussian boson sampling can be optimized by a proper design and training of the neural network weights. The results are potentially useful to the creation of new sources and complex circuits for quantum technologies.
C. Conti, Quantum Machine Intelligence (2021) 3:26
WHAT QUANTUM OPTICS, QUANTUM INFORMATION AND QUANTUM MATERIAL THEORY CAN TEACH US ABOUT GRAVITY AND FUNDAMENTAL QUANTUM MECHANICS
There is only one time
We draw a picture of physical systems that allows us to recognize what “time” is by requiring consistency with the way that time enters the fundamental laws of Physics. Elements of the picture are two non-interacting and yet entangled quantum systems, one of which acting as a clock. The setting is based on the Page and Wootters mechanism, with tools from large-N quantum approaches. Starting from an overall quantum description, we first take the classical limit of the clock only, and then of the clock and the evolving system altogether; we thus derive the Schrödinger equation in the first case, and the Hamilton equations of motion in the second. This work shows that there is not a “quantum time”, possibly opposed to a “classical” one; there is only one time, and it is a manifestation of entanglement.
C. Foti, A. Coppo, G. Barni and A Cuccoli, Nature Communications 12, 1787 (2021)
ULTRASTRONG LIGHT-MATTER COUPLING AND QUANTUM SENSING
Critical Quantum Metrology with a Finite-Component Quantum Phase Transition
Physical systems close to a quantum phase transition exhibit a divergent susceptibility, suggesting that an arbitrarily high precision may be achieved by exploiting quantum critical systems as probes to estimate a physical parameter. However, such an improvement in sensitivity is counterbalanced by the closing of the energy gap, which implies a critical slowing down and an inevitable growth of the protocol duration. Here, we design different metrological protocols that exploit the superradiant phase transition of the quantum Rabi model, a finite-component system composed of a single two-level atom interacting with a single bosonic mode. We show that, in spite of the critical slowing down, critical quantum optical probes can achieve a quantum-enhanced time scaling of the sensitivity in frequency-estimation protocols.
Universal Spectral Features of Ultrastrongly Coupled Systems
IWe identify universal properties of the low-energy subspace of a wide class of quantum optical models in the ultrastrong coupling limit, where the coupling strength dominates over all other energy scales in the system. We show that the symmetry of the light-matter interaction is at the origin of a twofold degeneracy in the spectrum. We prove analytically this result for bounded Hamiltonians and extend it to a class of models with unbounded operators. As a consequence, we show that the emergence of superradiant phases previously investigated in the context of critical phenomena, is a general property of the ultrastrong coupling limit. The set of models we consider encompasses different scenarios of possible interplay between critical behavior and superradiance.
QUANTUM DISSIPATIVE DYNAMICS IN THE BARDEEN-COOPER-SCHRIEFFER THEORY OF SUPERCONDUCTIVITY
Emergent parametric resonances and time-crystal phases in driven Bardeen-Cooper-Schrieffer systems
We study the out-of-equilibrium dynamics of a Bardeen-Cooper-Schrieffer condensate subject to a periodic drive. We demonstrate that the combined effect of drive and interactions results in emerging parametric resonances, analogous to a vertically driving pendulum. In particular, Arnold tongues appear when the driving frequency matches 2Δ0/n, with n a natural number, and Δ0 the equilibrium gap parameter. Inside the Arnold tongues we find a commensurate time-crystal condensate which retains the U(1) symmetry breaking of the parent superfluid/superconducting phase and shows an additional time-translational symmetry breaking. Outside these tongues, the synchronized collective Higgs mode found in quench protocols is stabilized without the need of a strong perturbation. Our results are directly relevant to cold-atom and condensed-matter systems and do not require very long energy relaxation times to be observed.
Nonlinear Dynamics of Driven Superconductors with Dissipation
In the absence of dissipation a periodically driven BCS superconductor can enter a coherent nonlinear regime of collective Rabi oscillations which last for arbitrary long times [Ojeda Collado et al., Phys. Rev. B 98, 214519 (2018)]. Here we show that dissipation effects introduce dramatic changes: (i) The collective Rabi mode becomes a transient. (ii) At long times a steady state is reached showing strong nonlinear effects for large enough drive strength. We identify the physical parameters governing the various crossovers and present a detailed computation of time- and angle-resolved photoemission spectroscopy (tr-ARPES) and time-resolved tunneling spectra aiming at detecting the collective Rabi oscillations and the steady-state nonlinearities. We show also that second harmonic generation is allowed for a drive which acts on the BCS coupling constant.
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International Day of Girls and Women in Science
Aula Amaldi, Edificio Marconi, Sapienza Università di Roma
Locandina evento
sito
L’11 Febbraio è stato nominato dalle Nazioni Unite “International Day of Women and Girls in Science” con le finalità di: “…achieve full and equal access to and participation in science for women and girls, and further achieve gender equality and the empowerment of women and girls”.
In questa importante occasione, il Dipartimento di Fisica della Sapienza organizza un evento rivolto alle studentesse e agli studenti, al personale docente e ricercatore, e a tutte le persone interessate con la finalità di condividere dati, evidenziare stereotipi e discutere azioni positive attraverso il confronto con altre realtà nazionali e internazionali.
Contatti: Irene Giardina Raffaella Schneider raffaella.schneider@uniroma1.it
Messaggio del Preside della Facoltà di Scienze Matematichem Fisiche e Naturali, Prof. V. Nesi
Locandina Scienza Coatta
Programma
15:00 Introduzione e saluti – Valeria Ferrari (Dipartimento di Fisica, Sapienza Università di Roma)
Le statistiche
15:05 Il nostro Dipartimento nel panorama nazionale – Paolo Mataloni (Dipartimento di Fisica, Sapienza Università di Roma)
15:20 Il CNR nel Dipartimento e i dati nazionali – Barbara Ruzicka (Istituto dei Sistemi Complessi – CNR)
15:30 L’INFN nel Dipartimento e i dati nazionali – Marcella Diemoz (INFN – Roma 1)
15:40 Il progetto GENERA e il panorama internazionale – Roberta Antolini (INFN – Laboratori Nazionali del Gran Sasso)
15:50 Domande
Uno sguardo esterno
16:00 Stereotipi e bias inconsapevoli – Flavia Zucco (Associazione Donne e Scienza)
16:20 Azioni positive: l’esempio dell’Olanda – Annalisa Fasolino (Radboud University, Nijmegen)
16:40 Presentazione della mostra: da Roma al Mondo a cura delle dottorande del Dipartimento di Fisica, Sapienza Università di Roma
16:50 Coffee break e visita della mostra
17:20 Tavola Rotonda: dalla consapevolezza alle azioni positive
Partecipano: Giorgio Parisi (Presidente dell’Accademia Nazionale dei Lincei), Paolo Mataloni (Direttore del Dipartimento di Fisica, Sapienza Università di Roma), Speranza Falciano (Vice Presidente dell’INFN, TBC), Maria Rosaria Masullo (Comitato Unico di Garanzia dell’INFN), tutte le relatrici e i relatori che sono intervenuti.
18:00 La Scienza Coatta: “Pe dilla tutta live show”
18:30 Incontro e discussione con le scienziate che lavorano nel Dipartimento
A silver path for high temperature superconductivity
Superconductors are materials that conduct electricity without loss of energy when cooled to sufficiently low temperatures. This sort of perpetual movement of electrons allows the creation of large magnetic fields for applications such as magnetic resonance imaging, which is used in hospitals for diagnostics or experiments for the discovery of new particles in large CERN accelerators. These niche applications could become much more widespread if one could avoid having to cool the materials at very low temperatures. This is why, since their discovery in 1911 there has been a race to rise the working temperature up to the “Holy Grail”, superconductivity at room temperature. So far, the ambient pressure record has been obtained with a family of ceramic materials (copper oxides) that have to be cooled “only” up to -140 ℃ and whose discovery earned the Nobel Prize for Physics at Bednorz and Müller in 1987. Curiously, the base materials for making these superconductors are not even conductors but insulating ceramics similar to porcelain but with very peculiar characteristics that defy the simplest theories on the conductivity of the solid and strong quantum fluctuations that are considered the “fertilizer” of superconductivity at high temperature. Only after an appropriate chemical substitution become metallic and superconducting. Now, a team of researchers from Institutes of the National Research Council (ISMN, SPIN, ISC) together with a team of researchers from Poland, the United Kingdom, Slovenia, the United States and the Slovak Republic have proposed a new family of compounds. They have shown that they can reproduce the same “quantum fertilizer” in materials with silver and fluoride instead of copper and oxygen. The hope now is to find the right substitutions that lead to the discovery of new superconductors that can operate at even higher temperatures. The consequences would be revolutionary in fields such as the transport of electricity and electronics. The research was published in Proceeding of the National Academy of Sciences https://www.pnas.org/content/early/2019/01/15/1812857116
International Day of Girls and Women in Science
Aula Amaldi, Edificio Marconi, Sapienza Università di Roma
Locandina evento
sito
L’11 Febbraio è stato nominato dalle Nazioni Unite “International Day of Women and Girls in Science” con le finalità di: “…achieve full and equal access to and participation in science for women and girls, and further achieve gender equality and the empowerment of women and girls”.
In questa importante occasione, il Dipartimento di Fisica della Sapienza organizza un evento rivolto alle studentesse e agli studenti, al personale docente e ricercatore, e a tutte le persone interessate con la finalità di condividere dati, evidenziare stereotipi e discutere azioni positive attraverso il confronto con altre realtà nazionali e internazionali.
Contatti: Irene Giardina Raffaella Schneider raffaella.schneider@uniroma1.it
Messaggio del Preside della Facoltà di Scienze Matematichem Fisiche e Naturali, Prof. V. Nesi
Locandina Scienza Coatta
Programma
15:00 Introduzione e saluti – Valeria Ferrari (Dipartimento di Fisica, Sapienza Università di Roma)
Le statistiche
15:05 Il nostro Dipartimento nel panorama nazionale – Paolo Mataloni (Dipartimento di Fisica, Sapienza Università di Roma)
15:20 Il CNR nel Dipartimento e i dati nazionali – Barbara Ruzicka (Istituto dei Sistemi Complessi – CNR)
15:30 L’INFN nel Dipartimento e i dati nazionali – Marcella Diemoz (INFN – Roma 1)
15:40 Il progetto GENERA e il panorama internazionale – Roberta Antolini (INFN – Laboratori Nazionali del Gran Sasso)
15:50 Domande
Uno sguardo esterno
16:00 Stereotipi e bias inconsapevoli – Flavia Zucco (Associazione Donne e Scienza)
16:20 Azioni positive: l’esempio dell’Olanda – Annalisa Fasolino (Radboud University, Nijmegen)
16:40 Presentazione della mostra: da Roma al Mondo a cura delle dottorande del Dipartimento di Fisica, Sapienza Università di Roma
16:50 Coffee break e visita della mostra
17:20 Tavola Rotonda: dalla consapevolezza alle azioni positive
Partecipano: Giorgio Parisi (Presidente dell’Accademia Nazionale dei Lincei), Paolo Mataloni (Direttore del Dipartimento di Fisica, Sapienza Università di Roma), Speranza Falciano (Vice Presidente dell’INFN, TBC), Maria Rosaria Masullo (Comitato Unico di Garanzia dell’INFN), tutte le relatrici e i relatori che sono intervenuti.
18:00 La Scienza Coatta: “Pe dilla tutta live show”
18:30 Incontro e discussione con le scienziate che lavorano nel Dipartimento
A silver path for high temperature superconductivity
Superconductors are materials that conduct electricity without loss of energy when cooled to sufficiently low temperatures. This sort of perpetual movement of electrons allows the creation of large magnetic fields for applications such as magnetic resonance imaging, which is used in hospitals for diagnostics or experiments for the discovery of new particles in large CERN accelerators. These niche applications could become much more widespread if one could avoid having to cool the materials at very low temperatures. This is why, since their discovery in 1911 there has been a race to rise the working temperature up to the “Holy Grail”, superconductivity at room temperature. So far, the ambient pressure record has been obtained with a family of ceramic materials (copper oxides) that have to be cooled “only” up to -140 ℃ and whose discovery earned the Nobel Prize for Physics at Bednorz and Müller in 1987. Curiously, the base materials for making these superconductors are not even conductors but insulating ceramics similar to porcelain but with very peculiar characteristics that defy the simplest theories on the conductivity of the solid and strong quantum fluctuations that are considered the “fertilizer” of superconductivity at high temperature. Only after an appropriate chemical substitution become metallic and superconducting. Now, a team of researchers from Institutes of the National Research Council (ISMN, SPIN, ISC) together with a team of researchers from Poland, the United Kingdom, Slovenia, the United States and the Slovak Republic have proposed a new family of compounds. They have shown that they can reproduce the same “quantum fertilizer” in materials with silver and fluoride instead of copper and oxygen. The hope now is to find the right substitutions that lead to the discovery of new superconductors that can operate at even higher temperatures. The consequences would be revolutionary in fields such as the transport of electricity and electronics. The research was published in Proceeding of the National Academy of Sciences https://www.pnas.org/content/early/2019/01/15/1812857116
International Day of Girls and Women in Science
Aula Amaldi, Edificio Marconi, Sapienza Università di Roma
Locandina evento
sito
L’11 Febbraio è stato nominato dalle Nazioni Unite “International Day of Women and Girls in Science” con le finalità di: “…achieve full and equal access to and participation in science for women and girls, and further achieve gender equality and the empowerment of women and girls”.
In questa importante occasione, il Dipartimento di Fisica della Sapienza organizza un evento rivolto alle studentesse e agli studenti, al personale docente e ricercatore, e a tutte le persone interessate con la finalità di condividere dati, evidenziare stereotipi e discutere azioni positive attraverso il confronto con altre realtà nazionali e internazionali.
Contatti: Irene Giardina Raffaella Schneider raffaella.schneider@uniroma1.it
Messaggio del Preside della Facoltà di Scienze Matematichem Fisiche e Naturali, Prof. V. Nesi
Locandina Scienza Coatta
Programma
15:00 Introduzione e saluti – Valeria Ferrari (Dipartimento di Fisica, Sapienza Università di Roma)
Le statistiche
15:05 Il nostro Dipartimento nel panorama nazionale – Paolo Mataloni (Dipartimento di Fisica, Sapienza Università di Roma)
15:20 Il CNR nel Dipartimento e i dati nazionali – Barbara Ruzicka (Istituto dei Sistemi Complessi – CNR)
15:30 L’INFN nel Dipartimento e i dati nazionali – Marcella Diemoz (INFN – Roma 1)
15:40 Il progetto GENERA e il panorama internazionale – Roberta Antolini (INFN – Laboratori Nazionali del Gran Sasso)
15:50 Domande
Uno sguardo esterno
16:00 Stereotipi e bias inconsapevoli – Flavia Zucco (Associazione Donne e Scienza)
16:20 Azioni positive: l’esempio dell’Olanda – Annalisa Fasolino (Radboud University, Nijmegen)
16:40 Presentazione della mostra: da Roma al Mondo a cura delle dottorande del Dipartimento di Fisica, Sapienza Università di Roma
16:50 Coffee break e visita della mostra
17:20 Tavola Rotonda: dalla consapevolezza alle azioni positive
Partecipano: Giorgio Parisi (Presidente dell’Accademia Nazionale dei Lincei), Paolo Mataloni (Direttore del Dipartimento di Fisica, Sapienza Università di Roma), Speranza Falciano (Vice Presidente dell’INFN, TBC), Maria Rosaria Masullo (Comitato Unico di Garanzia dell’INFN), tutte le relatrici e i relatori che sono intervenuti.
18:00 La Scienza Coatta: “Pe dilla tutta live show”
18:30 Incontro e discussione con le scienziate che lavorano nel Dipartimento
A silver path for high temperature superconductivity
Superconductors are materials that conduct electricity without loss of energy when cooled to sufficiently low temperatures. This sort of perpetual movement of electrons allows the creation of large magnetic fields for applications such as magnetic resonance imaging, which is used in hospitals for diagnostics or experiments for the discovery of new particles in large CERN accelerators. These niche applications could become much more widespread if one could avoid having to cool the materials at very low temperatures. This is why, since their discovery in 1911 there has been a race to rise the working temperature up to the “Holy Grail”, superconductivity at room temperature. So far, the ambient pressure record has been obtained with a family of ceramic materials (copper oxides) that have to be cooled “only” up to -140 ℃ and whose discovery earned the Nobel Prize for Physics at Bednorz and Müller in 1987. Curiously, the base materials for making these superconductors are not even conductors but insulating ceramics similar to porcelain but with very peculiar characteristics that defy the simplest theories on the conductivity of the solid and strong quantum fluctuations that are considered the “fertilizer” of superconductivity at high temperature. Only after an appropriate chemical substitution become metallic and superconducting. Now, a team of researchers from Institutes of the National Research Council (ISMN, SPIN, ISC) together with a team of researchers from Poland, the United Kingdom, Slovenia, the United States and the Slovak Republic have proposed a new family of compounds. They have shown that they can reproduce the same “quantum fertilizer” in materials with silver and fluoride instead of copper and oxygen. The hope now is to find the right substitutions that lead to the discovery of new superconductors that can operate at even higher temperatures. The consequences would be revolutionary in fields such as the transport of electricity and electronics. The research was published in Proceeding of the National Academy of Sciences https://www.pnas.org/content/early/2019/01/15/1812857116
International Day of Girls and Women in Science
Aula Amaldi, Edificio Marconi, Sapienza Università di Roma
Locandina evento
sito
L’11 Febbraio è stato nominato dalle Nazioni Unite “International Day of Women and Girls in Science” con le finalità di: “…achieve full and equal access to and participation in science for women and girls, and further achieve gender equality and the empowerment of women and girls”.
In questa importante occasione, il Dipartimento di Fisica della Sapienza organizza un evento rivolto alle studentesse e agli studenti, al personale docente e ricercatore, e a tutte le persone interessate con la finalità di condividere dati, evidenziare stereotipi e discutere azioni positive attraverso il confronto con altre realtà nazionali e internazionali.
Contatti: Irene Giardina Raffaella Schneider raffaella.schneider@uniroma1.it
Messaggio del Preside della Facoltà di Scienze Matematichem Fisiche e Naturali, Prof. V. Nesi
Locandina Scienza Coatta
Programma
15:00 Introduzione e saluti – Valeria Ferrari (Dipartimento di Fisica, Sapienza Università di Roma)
Le statistiche
15:05 Il nostro Dipartimento nel panorama nazionale – Paolo Mataloni (Dipartimento di Fisica, Sapienza Università di Roma)
15:20 Il CNR nel Dipartimento e i dati nazionali – Barbara Ruzicka (Istituto dei Sistemi Complessi – CNR)
15:30 L’INFN nel Dipartimento e i dati nazionali – Marcella Diemoz (INFN – Roma 1)
15:40 Il progetto GENERA e il panorama internazionale – Roberta Antolini (INFN – Laboratori Nazionali del Gran Sasso)
15:50 Domande
Uno sguardo esterno
16:00 Stereotipi e bias inconsapevoli – Flavia Zucco (Associazione Donne e Scienza)
16:20 Azioni positive: l’esempio dell’Olanda – Annalisa Fasolino (Radboud University, Nijmegen)
16:40 Presentazione della mostra: da Roma al Mondo a cura delle dottorande del Dipartimento di Fisica, Sapienza Università di Roma
16:50 Coffee break e visita della mostra
17:20 Tavola Rotonda: dalla consapevolezza alle azioni positive
Partecipano: Giorgio Parisi (Presidente dell’Accademia Nazionale dei Lincei), Paolo Mataloni (Direttore del Dipartimento di Fisica, Sapienza Università di Roma), Speranza Falciano (Vice Presidente dell’INFN, TBC), Maria Rosaria Masullo (Comitato Unico di Garanzia dell’INFN), tutte le relatrici e i relatori che sono intervenuti.
18:00 La Scienza Coatta: “Pe dilla tutta live show”
18:30 Incontro e discussione con le scienziate che lavorano nel Dipartimento
A silver path for high temperature superconductivity
Superconductors are materials that conduct electricity without loss of energy when cooled to sufficiently low temperatures. This sort of perpetual movement of electrons allows the creation of large magnetic fields for applications such as magnetic resonance imaging, which is used in hospitals for diagnostics or experiments for the discovery of new particles in large CERN accelerators. These niche applications could become much more widespread if one could avoid having to cool the materials at very low temperatures. This is why, since their discovery in 1911 there has been a race to rise the working temperature up to the “Holy Grail”, superconductivity at room temperature. So far, the ambient pressure record has been obtained with a family of ceramic materials (copper oxides) that have to be cooled “only” up to -140 ℃ and whose discovery earned the Nobel Prize for Physics at Bednorz and Müller in 1987. Curiously, the base materials for making these superconductors are not even conductors but insulating ceramics similar to porcelain but with very peculiar characteristics that defy the simplest theories on the conductivity of the solid and strong quantum fluctuations that are considered the “fertilizer” of superconductivity at high temperature. Only after an appropriate chemical substitution become metallic and superconducting. Now, a team of researchers from Institutes of the National Research Council (ISMN, SPIN, ISC) together with a team of researchers from Poland, the United Kingdom, Slovenia, the United States and the Slovak Republic have proposed a new family of compounds. They have shown that they can reproduce the same “quantum fertilizer” in materials with silver and fluoride instead of copper and oxygen. The hope now is to find the right substitutions that lead to the discovery of new superconductors that can operate at even higher temperatures. The consequences would be revolutionary in fields such as the transport of electricity and electronics. The research was published in Proceeding of the National Academy of Sciences https://www.pnas.org/content/early/2019/01/15/1812857116
In the news: Anderson Localization