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Relative entropy serves as a cornerstone concept in quantum information theory. In this work, we study relative entropy of random states from major generic state models of Hilbert-Schmidt and Bures-Hall ensembles. In particular, we derive…

Mathematical Physics · Physics 2026-05-28 Lu Wei

States of a quantum mechanical system are represented by rays in a complex Hilbert space. The space of rays has, naturally, the structure of a K\"ahler manifold. This leads to a geometrical formulation of the postulates of quantum mechanics…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Abhay Ashtekar , Troy A. Schilling

The geometric formulation of quantum mechanics is a very interesting field of research which has many applications in the emerging field of quantum computation and quantum information, such as schemes for optimal quantum computers. In this…

Quantum Physics · Physics 2014-04-24 Ole Andersson , Hoshang Heydari

Statistical formulations of thermodynamic entropy, such as those by Boltzmann and Gibbs, were originally developed for classical systems and are well understood in that context. However, the foundational aspects of quantum statistical…

Quantum Physics · Physics 2025-10-08 Smitarani Mishra , Shaon Sahoo

The study of conditional $q$-entropies in composite quantum systems has recently been the focus of considerable interest, particularly in connection with the problem of separability. The $q$-entropies depend on the density matrix $\rho$…

Quantum Physics · Physics 2009-11-10 J. Batle , A. R. Plastino , M. Casas , A. Plastino

When an optimal measurement is made on a qubit and what we call an Unbiased Mixture of the resulting ensembles is taken, then the post measurement density matrix is shown to be related to the pre-measurement density matrix through a simple…

Quantum Physics · Physics 2009-11-10 Chirag Dhara , N. D. Hari Dass

Quantum systems with real energies generated by an apparently non-Hermitian Hamiltonian may re-acquire the consistent probabilistic interpretation via an ad hoc metric which specifies the set of observables in the updated Hilbert space of…

Quantum Physics · Physics 2008-05-14 Miloslav Znojil

In Quantum Physics, a measurement is represented by a projection on some closed subspace of a Hilbert space. We study algebras of operators that abstract from the algebra of projections on closed subspaces of a Hilbert space. The properties…

Quantum Physics · Physics 2007-05-23 Daniel Lehmann , Kurt Engesser , Dov M. Gabbay

Precise rules are developed in order to formalize the reasoning processes involved in standard non-relativistic quantum mechanics, with the help of analogies from classical physics. A classical or quantum description of a mechanical system…

Quantum Physics · Physics 2007-05-23 Robert B. Griffiths

This work outlines a consistent method of identifying subsystems in finite-dimensional Hilbert spaces, independent of the underlying inner-product structure. Such Hilbert spaces arise in $\mathcal{P}\mathcal{T}$-symmetric quantum mechanics,…

Quantum Physics · Physics 2025-03-25 Himanshu Badhani , Sibasish Ghosh

We provide sufficient and necessary conditions guaranteeing equations $(A+B)^*=A^*+B^*$ and $(AB)^*=B^*A^*$ concerning densely defined unbounded operators $A,B$ between Hilbert spaces. We also improve the perturbation theory of selfadjoint…

Functional Analysis · Mathematics 2015-07-31 Zoltán Sebestyén , Zsigmond Tarcsay

Quantum mechanics can emerge from classical statistics. A typical quantum system describes an isolated subsystem of a classical statistical ensemble with infinitely many classical states. The state of this subsystem can be characterized by…

Quantum Physics · Physics 2015-05-13 C. Wetterich

We present a general method to compute canonical averages for physical models sampled via quantum or classical quadratic unconstrained binary optimization (QUBO). First, we introduce a histogram reweighting scheme applicable to QUBO-based…

Quantum Physics · Physics 2025-05-07 Francesco Slongo , Cristian Micheletti

In quantum theory, equilibrium statistical mechanics is usually formulated through the canonical ensemble, whose privileged status is tied to the Euclidean continuation of time evolution. The microcanonical ensemble, by contrast, is…

Quantum Physics · Physics 2026-03-13 Loris Di Cairano

We find equivalent hypergeometric- and difference-equation-based formulas, $Q(k,\alpha)= G_1^k(\alpha) G_2^k(\alpha)$, for $k = -1, 0, 1,\ldots,9$, for that (rational-valued) portion of the total separability probability for generalized…

Quantum Physics · Physics 2015-04-20 Paul B. Slater

This paper proposes a quantum circuit for computing the mean value from a given set of quantum states. The circuit consults a Quantum Random Access Memory to get the values of the set, and by using superposition, interference and…

Quantum Physics · Physics 2019-12-02 Amanuel Tamirat

A statistical model M is a family of probability distributions, characterised by a set of continuous parameters known as the parameter space. This possesses natural geometrical properties induced by the embedding of the family of…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Dorje C. Brody , Lane P. Hughston

The random matrix ensembles are applied to the quantum statistical two-dimensional systems of electrons. The quantum systems are studied using the finite dimensional real, complex and quaternion Hilbert spaces of the eigenfunctions. The…

Statistical Mechanics · Physics 2015-06-24 Maciej M. Duras

We revisit the relationship between quantum separability and the sign of the relative q-entropies of composite quantum systems. The q-entropies depend on the density matrix eigenvalues p_i through the quantity omega_q = sum_i p_i^q. Renyi's…

Quantum Physics · Physics 2016-09-08 J. Batle , A. R. Plastino , M. Casas , A. Plastino

We derive an exact expression for the quantumness of a Hilbert space (defined in quant-ph/0302092), and show that in composite Hilbert spaces the signal states must contain at least some entangled states in order to achieve such a…

Quantum Physics · Physics 2007-05-23 Christopher A. Fuchs