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10TH International workshop on quantum phase transitions in nuclei and many-body systems

11–15 Jul 2022
Dubrovnik, Croatia
Europe/Zagreb timezone

Info

Session

Excited-state quantum phase transitions

15 Jul 2022, 09:00
IUC

IUC

Don Frana Bulića 4, Dubrovnik

Conveners

Excited-state quantum phase transitions

  • Pavel Cejnar
  • Pavel Stransky

Excited-state quantum phase transitions

  • Pavel Cejnar
  • Pavel Stransky

Presentation materials

There are no materials yet.

  1. 80. Introduction to the physics of ESQPTs
    Pavel Cejnar (Inst. of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles Uni.)
    15/07/2022, 09:00
    Excited-state quantum phase transitions

    The talk will overview some recent contributions to the ESQPT field. The main attention will be focused on the recent generalization of the ESQPT concept to systems with continuous spectra, particularly to the one-dimensional tunneling problem [1,2].

    References:

    [1] P. Stránský, M. Šindelka, M. Kloc, P. Cejnar, Phys. Rev. Lett. 125, 020401 (2020).
    [2] P. Stránský, M. Šindelka, P....

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  2. 38. Analogs of QPTs and ESQPTs in a dissipative spin model
    Jorge Dukelsky
    15/07/2022, 09:30
    Excited-state quantum phase transitions

    We will present a model of a quantum collective spin weakly coupled to a spin-polarized Markovian environment which displays extremely exotic spectral properties [1]. As a function of the environment magnetization the spectrum is divided in to two regions by a divergence in the density of Liouvillian eigenvalues. This Liouvillian spectral phase transition is the analog of the ESQPTs in closed...

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  3. 39. Constant of motion identifying excited-state quantum phases and some applications to quantum optical models
    Armando Relaño (Universidad Complutense de Madrid)
    15/07/2022, 10:00
    Excited-state quantum phase transitions

    ESQPTs have an important drawback compared with quantum and thermal phase transitions: it is not easy to define two different phases, with different equilibrium properties, separated by the corresponding critical energy. In this talk, I will review our work [1], where we proposed a way to address this issue. We find an operator which is a constant of motion only in one of these two phases....

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  4. 40. Theory of dynamical phase transitions driven by excited-state quantum phase transitions
    Ángel L. Corps (Instituto de Estructura de la Materia, IEM-CSIC)
    15/07/2022, 10:30
    Excited-state quantum phase transitions

    During recent years there has been a growing interest in the different kinds of phase transition that many-body quantum systems may exhibit as well as in the thermodynamic properties associated to the resulting quantum phases. Besides the well-known quantum phase transition, occurring in the ground-state of a physical system as a certain control parameter is varied, and its generalization to...

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  5. 79. Stabilization of quantum states at ESQPTs
    Pavel Stránský (Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University)
    15/07/2022, 11:30
    Excited-state quantum phase transitions

    It is well known that ESQPTs can either enhance or suppress survival probability of the initial state after a quantum quench. These effects, theoretically demonstrated particularly in the Lipkin model, the Tavis-Cummings model and the Rabi model, see e.g. Refs. [1,2], represent a possible experimental test of criticality in the excited domain. We will show the common origin of both these...

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  6. 57. Pairwise kissing of excited states in a squeezed Kerr-oscillator
    Rodrigo Cortinas
    15/07/2022, 12:00
    Excited-state quantum phase transitions

    Recent advances in the control of superconducting circuits opened new possibilities for the investigation of fundamental quantum phenomena. In this work, we demonstrate the transition into the ``Schrödinger-cat regime'' of a Kerr-oscillator as it is progressively dressed by squeezed microwave light.
    We discover that the lifetime of the degenerate ground states in our experiment increases in...

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  7. 73. Detection of excited state quantum phase transition with a Kerr-nonlinear resonator
    Curro Perez-Bernal (Universidad de Huelva), Lea Santos
    15/07/2022, 12:30
    Excited-state quantum phase transitions

    Kerr nonlinear resonators have been used to study dynamical bifurcation, to squeeze quantum fluctuations, and to prepare Schroedinger cat states. They can be realized by coupling a superconducting two-level system to a microwave cavity. This is also the setup for the transmon qubit adopted by companies such as IBM, Google, and Rigetti. We show that the experimentally detected spectrum of a...

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  8. 61. Eigenstate metamorphosis in the Bose Hubbard model
    Andreas Buchleitner (Albert-Ludwigs-Universitaet Freiburg)
    Excited-state quantum phase transitions

    We will discuss the metamorphosis of the spectrum and of the eigenstates of the Bose-Hubbard Hamiltonian at the transition from integrability to (quantum) chaos,
    addressing universal as well as distinctive properties in the chaotic domain.
    We will further contrast the spectral information with dynamical features directly accessible in cold atom experiments, with special attention to...

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