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Non-Gaussian entangled states play a crucial role in harnessing quantum advantage in continuous-variable quantum information. However, how to fully characterize N-partite (N > 3) non-Gaussian entanglement without quantum state tomography…

Quantum Physics · Physics 2023-12-05 Da Zhang , David Barral , Yanpeng Zhang , Kamel Bencheikh

We consider a closed quantum system subjected to stochastic Poissonian resetting with rate $r$ to its initial state. Resetting drives the system to a nonequilibrium stationary state (NESS) with a mixed density matrix which has both…

Quantum Physics · Physics 2024-03-29 Manas Kulkarni , Satya N. Majumdar

We theoretically derive the probability densities of the entanglement measures of a pure non-ergodic many-body state, represented in a bipartite product basis and with its reduced density matrix described by a generalized, multi-parametric…

Quantum Physics · Physics 2024-12-11 Devanshu Shekhar , Pragya Shukla

We explore conditions on the covariance matrices of a consistent chain of mean zero finite mode Gaussian states in order that the chain may be exchangeable or stationary. For an exchangeable chain our conditions are necessary and…

Quantum Physics · Physics 2015-10-16 K. R. Parthasarathy , Ritabrata Sengupta

We study the capacity of entanglement as an alternative to entanglement entropies in estimating the degree of entanglement of quantum bipartite systems over fermionic Gaussian states. In particular, we derive the exact and asymptotic…

Mathematical Physics · Physics 2023-10-05 Youyi Huang , Lu Wei

In this work, we explore both the internal and external atomic degrees of freedom to observe quantum entanglement between the modes produced by a mirrorless optical parametric oscillator operating below the oscillation threshold in a sample…

Quantum Physics · Physics 2026-02-12 G. C. Borba , R. S. N. Moreira , L. S. Cruz , M. Martinelli , D. Felinto , J. W. R. Tabosa

The time evolution of the entanglement entropy in non-equilibrium quantum systems provides crucial information about the structure of the time-dependent state. For quantum quench protocols, by combining a quasiparticle picture for the…

Statistical Mechanics · Physics 2018-03-30 Vincenzo Alba , Pasquale Calabrese

Repeated measurements can induce entanglement phase transitions in the dynamics of quantum systems. Interacting models, both chaotic and integrable, generically show a stable volume-law entangled phase at low measurement rates which…

Quantum Physics · Physics 2024-05-21 Luca Lumia , Emanuele Tirrito , Rosario Fazio , Mario Collura

We generalise the Gaussian formalism of Continuous Variable (CV) systems to describe their interactions with qubits/qudits that result in quantum superpositions of Gaussian processes. To this end, we derive a new set of equations in closed…

Quantum Physics · Physics 2025-10-02 Lorenzo Braccini , Sougato Bose , Alessio Serafini

We investigate entanglement between electronic and nuclear degrees of freedom for a model nonadiabatic system. We find that entanglement (measured by the von Neumann entropy of the subsystem for the eigenstates) is large in a statistical…

Quantum Physics · Physics 2009-11-10 Hiroshi Fujisaki

We outline the basic questions that are being studied in the theory of entanglement. Following a brief review of some of the main achievements of entanglement theory for finite-dimensional quantum systems such as qubits, we will consider…

Quantum Physics · Physics 2009-09-29 J. Eisert , M. B. Plenio

We use quantum entanglement witnesses derived from Gaussian operators to study the separable criteria of continuous variable states. We transform the validity of a Gaussian witness to a Bosonic Gaussian channel problem. It follows that the…

Quantum Physics · Physics 2022-08-29 Xiao-yu Chen , Maoke Miao , Rui Yin , Jiantao Yuan

Bipartite entanglement between two parties of a composite quantum system can be quantified in terms of the purity of one party and there always exists a pure state of the total system that maximizes it (and minimizes purity). When many…

Quantum Physics · Physics 2012-04-05 Cosmo Lupo , Stefano Mancini , Paolo Facchi , Giuseppe Florio , Saverio Pascazio

I propose the multi-mode squeezed thermal state based on the multi-mode pure entangled state. The correlation matrix of the state is characterized by two parameters. I then analysis the separable condition for this state, and calculating…

Quantum Physics · Physics 2009-11-10 Xiao-yu Chen

We study the behavior of bipartite entanglement at fixed von Neumann entropy. We look at the distribution of the entanglement spectrum, that is the eigenvalues of the reduced density matrix of a quantum system in a pure state. We report the…

Quantum Physics · Physics 2013-05-29 Paolo Facchi , Giuseppe Florio , Giorgio Parisi , Saverio Pascazio , Kazuya Yuasa

We use concepts from quantum cryptography to relate the entanglement in many-body mixed states to standard correlation functions. If a system can be used as a resource for distilling private keys -- random classical bits that are shared by…

Quantum Physics · Physics 2026-03-13 Samuel J. Garratt , Max McGinley

We define correlational (von Neumann) entropy for an individual quantum state of a system whose time-independent hamiltonian contains random parameters and is treated as a member of a statistical ensemble. This entropy is representation…

chao-dyn · Physics 2013-01-16 Valentin V. Sokolov , B. Alex Brown , Vladimir Zelevinsky

We study the statistical behaviour of quantum entanglement in bipartite systems over fermionic Gaussian states as measured by von Neumann entropy. The formulas of average von Neumann entropy with and without particle number constrains have…

Mathematical Physics · Physics 2023-10-31 Youyi Huang , Lu Wei

It is presented a generalization of the von Neumann mutual information in the context of Tsallis' nonextensive statistics. As an example, entanglement between two (two-level) quantum subsystems is discussed. Important changes occur in the…

Quantum Physics · Physics 2009-10-31 A. Vidiella-Barranco

The entanglement production in bipartite quantum systems is studied for initially unentangled product eigenstates of the subsystems, which are assumed to be quantum chaotic. Based on a perturbative computation of the Schmidt eigenvalues of…