OpenQMBP2023: New perspectives in the out-of-equilibrium dynamics of open many-body quantum systems

Session

Conference: Dissipative Many-Body Quantum Systems

13 juin 2023, 10:00

Institut Pascal

28. Negative tripartite information after quantum quenches in integrable systems

Vincenzo ALBA (University of Pisa)

13/06/2023 10:00

We build the quasiparticle picture for the tripartite mutual information (TMI) after quantum quenches in spin chains that can be mapped onto free-fermion theories. A nonzero TMI (equivalently, topological entropy) signals quantum correlations between three regions of a quantum many-body system. The TMI is sensitive to entangled multiplets of more than two quasiparticles, i.e., beyond the...

39. Inelastic Cooper pair tunneling in the strongly interacting regime

Jérôme ESTEVE (Laboratoire de Physique des Solides)

13/06/2023 10:25

Superconducting circuits have recently emerged as a new platform to explore the physics of open many body systems using microwave photons in strongly non-linear media. In this talk, we will present some experimental results that were obtained in Orsay and in Grenoble where photons confined in a waveguide interact strongly through an impurity, here a Josephson junction. The system may be driven...

40. Neural-Network Quantum States for Entanglement Phase Transitions

Filippo Vicentini (Ecole Polytechnique)

13/06/2023 11:00

The success of Machine Learning owes to the development of neural-networks, variational approximators that can efficiently represent unknown functions living in high-dimensional spaces. Recently, those techniques have been ported to the field of numerical physics and used to approximate inherently high dimensional objects such as the Many-Body Wave-Function [1] or Density-Matrix [2] in an...

41. Adiabatic atom losses in nearly integrable quantum gases

Jérôme Dubail (CNRS)

13/06/2023 11:25

Cold atom gases are never perfectly isolated, and they typically suffer from atom losses. Different mechanisms for losses can be present, which are distinguished by the number of atoms K (K = 1, 2, 3, . . . ) involved in each loss event. When the dynamics of the isolated gas is integrable, atom losses weakly break integrability, and the evolution of the gas can be captured by a slowly varying...

42. Phase transitions in finite-component systems: Superradiance beyond the Dicke paradigm

Alexandre LE BOITE (Laboratoire MPQ, CNRS, Université de Paris Cité)

13/06/2023 11:50

The experimental control of the coherent interaction between light and matter is one of the corner stones of the recent developments in the field of quantum technologies. In this context, cavity quantum electrodynamics has reached an important milestone in the last decade with the achievement of the ultrastrong coupling (USC) regime, where the coupling strength becomes comparable or even...

43. Comparing bipartite entropy growth in open-system matrix product simulation methods

Johannes SCHACHENMAYER (CESQ/ISIS, CNRS & University of Strasbourg)

13/06/2023 14:00

In this talk I will discuss the "entanglement" entropy growth dynamics in open spin models, comparing different matrix product representations of the many-body density matrix. Recently we discovered mechanisms behind a logarithmic growth of operator entanglement (OE) in XXZ model dynamics subjected to dephasing [1]. I will contrast this behavior to the growth of trajectory entanglement (TE),...

44. Effect of slow losses in quantum gases with short range interactions: UV divergence in higher dimensions and breakdown of Tan's relation in 1D gases

Isabelle Bouchoule

13/06/2023 14:25

We investigate the effect of losses on interacting quantum gases with contact interaction. We show that, for gases in dimension higher than one, assuming a vanishing correlation time of the reservoir where dissipation occurs leads to a divergence of the energy increase rate. This divergence orginiates from the ghost singularity of the wavefunction immediately after a loss event. We show how...

45. Quantum-Darwinism-encoding transitions

Xiangyu CAO (CNRS/LPENS)

13/06/2023 15:00

Quantum Darwinism (QD) is a theory of how classical objectivity emerges from quantum mechanics. Its key idea is that the environment has objective knowledge of a qubit only if small fractions of the former are correlated with the latter (like in a GHZ state). However generic unitary dynamics in a many-body system scrambles and encodes information, instead of broadcasting it. Are the two...

46. Continuous superradiance sustained by a stream of excited atoms

Martin ROBERT DE SAINT VINCENT (Laboratoire de Physique des Lasers, CNRS, USPN)

13/06/2023 15:25

Superradiance of cold atoms in an optical cavity can be harvested to act as an optical frequency reference. By using an electronic transition much narrower spectrally than the cavity mode (i.e., by operating in the bad cavity limit), the frequency of the outcoming light is little affected by mirror position fluctuations – a signifiant limitation to short term stability in standard optical...

47. Sensing dynamical phase transitions

Katarzyna Macieszczak (University of Warwick)

13/06/2023 15:50

We will consider a parallel quantum dot as an example of an open quantum system that can feature a strong parity symmetry. For the dot, due to the presence of interactions, this symmetry results in the bistability characterised by distinct particle currents, while its explicit breaking leads to metastability. We will discuss when parameters of the dynamics can be estimated by continuously...

38. TBA

Vincenzo ALBA (University of Pisa)