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We present a general way of quantifying the entropic uncertainty of quantum field configurations in phase space in terms of entropic distinguishability with respect to the vacuum. Our approach is based on the functional Husimi…

Quantum Physics · Physics 2024-07-24 Sara Ditsch , Tobias Haas

The Husimi distribution is proposed for a phase space analysis of quantum phase transitions in the Dicke model of spin-boson interactions. We show that the inverse participation ratio and Wehrl entropy of the Husimi distribution give sharp…

Quantum Physics · Physics 2014-09-24 E. Romera , R. del Real , M. Calixto

Adaptive quantum circuits, leveraging measurements and classical feedback, significantly expand the landscape of realizable quantum states compared to their non-adaptive counterparts, enabling the preparation of long-range entangled states…

Quantum Physics · Physics 2025-09-23 Guoding Liu , Junjie Chen , Xiongfeng Ma

We discuss some basic tools for an analysis of one-dimensionalquantum systems defined on a cyclic coordinate space. The basic features of the generalized coherent states, the complexifier coherent states are reviewed. These states are then…

Quantum Physics · Physics 2008-11-26 B. Bahr , H. J. Korsch

To reconstruct a mixed or pure quantum state of a spin s is possible through coherent states: its density matrix is fixed by the probabilities to measure the value s along 4s(s+1) appropriately chosen directions in space. Thus, after…

Quantum Physics · Physics 2007-05-23 Stefan Weigert

We propose the second moment of the Husimi distribution as a measure of complexity of quantum states. The inverse of this quantity represents the effective volume in phase space occupied by the Husimi distribution, and has a good…

Chaotic Dynamics · Physics 2009-11-07 Ayumu Sugita , Hirokazu Aiba

Covariant integral quantizations are based on the resolution of the identity by continuous or discrete families of normalised positive operator valued measures (POVM), which have appealing probabilistic content and which transform in a…

Quantum Physics · Physics 2022-09-27 Jean Pierre Gazeau , Romain Murenzi

The quantum state of a system of qubits can be represented by a Wigner function on a discrete phase space, each axis of the phase space taking values in a finite field. Within this framework, we show that one can make sense of the notion of…

Quantum Physics · Physics 2007-05-23 William K. Wootters , Daniel M. Sussman

We construct a complete set of Wannier functions which are localized at both given positions and momenta. This allows us to introduce the quantum phase space, onto which a quantum pure state can be mapped unitarily. Using its probability…

Statistical Mechanics · Physics 2015-06-10 Xizhi Han , Biao Wu

The Husimi distribution is proposed for a phase space analysis of quantum phase transitions in the two-dimensional $U(3)$ vibron model for $N$-size molecules. We show that the inverse participation ratio and Wehrl's entropy of the Husimi…

Quantum Physics · Physics 2014-09-22 M. Calixto , R. del Real , E. Romera

We introduce a variational method for simulating the dynamics of interacting open quantum spin systems. The method is based on the spin phase-space representation and variationally targets the Husimi-$Q$ function with an ansatz based on a…

Quantum Physics · Physics 2026-04-02 Jacopo Tosca , Zejian Li , Francesco Carnazza , Cristiano Ciuti

We show that the number of harmonics of the Wigner function, recently proposed as a measure of quantum complexity, can be also used to characterize quantum phase transitions. The non-analytic behavior of this quantity in the neighborhood of…

Quantum Physics · Physics 2015-06-17 Pinquan Qin , Wen-ge Wang , Giuliano Benenti , Giulio Casati

We develop a unified, information theoretic interpretation of the number-phase complementarity that is applicable both to finite-dimensional (atomic) and infinite-dimensional (oscillator) systems, with number treated as a discrete Hermitian…

Quantum Physics · Physics 2015-05-13 Subhashish Banerjee , R. Srikanth

Quantum complexity measures the difficulty of obtaining a given state starting from a typically unentangled state. In this work, we show that complexity, when defined through the minimization of a Riemannian cost functional over the…

Quantum Physics · Physics 2025-06-05 Nadir Samos Sáenz de Buruaga

We consider the problem of determining the spatial phase profile of a single-mode electromagnetic field. Our attention is on input states that are a statistical mixture of displaced and squeezed number states, a superset of Gaussian states.…

Optics · Physics 2024-07-09 Jacob Trzaska , Amit Ashok

This paper aims to stress the role of the Cahill-Glauber quasi-probability densities in defining, detecting, and quantifying the non-classicality of field states in quantum optics. The distance between a given pure state and the set of all…

Quantum Physics · Physics 2020-04-22 Paulina Marian , Tudor A. Marian

We investigate the role of a statistical complexity measure to assign equilibration in isolated quantum systems. While unitary dynamics preserve global purity, expectation values of observables often exhibit equilibration-like behavior,…

Quantum Physics · Physics 2025-08-14 Marcos G. Alpino , Tiago Debarba , Reinaldo O. Vianna , André T. Cesário

For one-dimensional continuous-variable quantum systems such as single-mode quantum optical systems, we give a quantification of the quantumness of such a system's state, {\rho}, by introducing the measure of quantumness, {\Xi}, which works…

Quantum Physics · Physics 2026-03-03 Ole Steuernagel , Hsien-Yi Hsieh , Yi-Ru Chen , Ray-Kuang Lee

We quantify the emergent complexity of quantum states near quantum critical points on regular 1D lattices, via complex network measures based on quantum mutual information as the adjacency matrix, in direct analogy to quantifying the…

Statistical Mechanics · Physics 2017-12-06 Marc Andrew Valdez , Daniel Jaschke , David L. Vargas , Lincoln D. Carr

We derive entropic inseparability criteria for the phase space representation of quantum states. In contrast to criteria involving differential entropies of marginal phase space distributions, our criteria are based on a joint distribution…

Quantum Physics · Physics 2022-01-10 Stefan Floerchinger , Martin Gärttner , Tobias Haas , Oliver R. Stockdale