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The quantum separability problem consists in deciding whether a bipartite density matrix is entangled or separable. In this work, we propose a machine learning pipeline for finding approximate solutions for this NP-hard problem in…

Quantum Physics · Physics 2023-12-12 Balthazar Casalé , Giuseppe Di Molfetta , Sandrine Anthoine , Hachem Kadri

The random matrix ensembles (RME) of quantum statistical Hamiltonian operators, e.g. Gaussian random matrix ensembles (GRME) and Ginibre random matrix ensembles (Ginibre RME), are applied to following quantum statistical systems: nuclear…

Statistical Mechanics · Physics 2007-05-23 Maciej M. Duras

An analytical expression for the first-order density matrix of a charged, two-dimensional, harmonically confined quantum gas, in the presence of a constant magnetic field is derived. In contrast to previous results available in the…

Statistical Mechanics · Physics 2009-11-11 Patrick Shea , Brandon P. van Zyl

The density matrix formalism which is widely used in the theory of measurements, quantum computing, quantum description of chemical and biological systems always imply the averaging over the states of the environment. In practice this is…

Quantum Physics · Physics 2007-05-23 M. V. Altaisky

Density matrices are powerful mathematical tools for the description of closed and open quantum systems. Recently, methods for the direct computation of density matrix elements in scalar quantum field theory were developed based on thermo…

High Energy Physics - Theory · Physics 2025-03-12 Christian Käding , Mario Pitschmann

We consider an ensemble of $2\times 2$ normal matrices with complex entries representing operators in the quantum mechanics of 2 - level parity-time reversal (PT) symmetric systems. The randomness of the ensemble is endowed by obtaining…

Mathematical Physics · Physics 2025-01-14 Stalin Abraham , A. Bhagwat , Sudhir Ranjan Jain

The density matrix of composite spin system is discussed in relation to the adjoint representation of unitary group U(n). The entanglement structure is introduced as an additional ingredient to the description of the linear space carrying…

Quantum Physics · Physics 2007-05-23 V. I. Man'ko , G. Marmo , E. C. G. Sudarshan , F. Zaccaria

By using the density matrix renormalization group (DMRG) technique, the incommensurate quantum Frenkel-Kontorova model is investigated numerically. It is found that when the quantum fluctuation is strong enough, the \emph{g}-function…

Other Condensed Matter · Physics 2009-11-11 B. Hu , J. X. Wang

The resources needed to conventionally characterize a quantum system are overwhelmingly large for high- dimensional systems. This obstacle may be overcome by abandoning traditional cornerstones of quantum measurement, such as general…

Quantum Physics · Physics 2016-05-17 Gregory A. Howland , Samuel H. Knarr , James Schneeloch , Daniel J. Lum , John C. Howell

The dynamical equation satisfied by the density matrix, when a quantum system is subjected to one or more constraints arising from conserved quantities, is derived. The resulting nonlinear motion of the density matrix has the property that…

Quantum Physics · Physics 2015-02-23 Dorje C. Brody , Anna C. T. Gustavsson , Lane P. Hughston

We consider a set of density matrices. All of which are written in the same orbital basis, but the orbital basis size is less than the total Hilbert space size. We ask how each density matrix is related to each of the others by establishing…

Quantum Physics · Physics 2024-09-05 Thomas E. Baker , Negar Seif

We propose that spatial density matrices, which are singularly important in the study of quantum entanglement, encode the electronic fluctuations and correlations responsible for covalent bonding. From these density matrices, we develop…

Strongly Correlated Electrons · Physics 2014-12-05 Norm M. Tubman , D. ChangMo Yang

Interaction-free measurement and quantum interrogation schemes can help in the detection of particles without interacting with them in a classical sense. We present a density matrix study of a quantum interrogation system designed for…

Quantum Physics · Physics 2007-05-23 Juan Carlos Garcia-Escartin , Pedro Chamorro-Posada

Non-uniform structures of nuclear matter are studied in a wide density-range. Using the density functional theory with a relativistic mean-field model, we examine non-uniform structures at sub-nuclear densities (nuclear ``pastas'') and at…

Impressive progress has been made in the past decade in the study of technological applications of varied types of quantum systems. With industry giants like IBM laying down their roadmap for scalable quantum devices with more than…

Quantum Physics · Physics 2021-09-15 Rishabh Gupta , Sabre Kais , Raphael D. Levine

We present a protocol that allows the estimation of any density matrix element for continuous-variable quantum states, without resorting to the complete reconstruction of the full density matrix. The algorithm adaptatively discretizes the…

Quantum Physics · Physics 2024-09-25 Virginia Feldman , Ariel Bendersky

Decoherence in quantum computer memory due to the inevitable coupling to the external environment is examined. We take the assumption that all quantum bits (qubits) interact with the same environment rather than the assumption of separate…

Quantum Physics · Physics 2009-10-30 Lu-Ming Duan , Guang-Can Guo

We show that every density matrix of an n-particle system prepared by a quantum network of constant depth is asymptotically commuting with the mean-field observables. We introduce certain pairs of hypersurfaces in the space of density…

Quantum Physics · Physics 2007-05-23 Dominik Janzing , Thomas Beth

A non-ergodic quantum state of a many body system is in general random as well as multi-parametric, former due to a lack of exact information due to complexity and latter reflecting its varied behavior in different parts of the Hilbert…

Quantum Physics · Physics 2023-06-21 Devanshu Shekhar , Pragya Shukla

We put forward a possible new interpretation and explanatory framework for quantum theory. The basic hypothesis underlying this new framework is that quantum particles are conceptual entities. More concretely, we propose that quantum…

Quantum Physics · Physics 2011-11-10 Diederik Aerts