English
Related papers

Related papers: Spectral Projections for Density Matrices in Quant…

200 papers

In this paper we propose the idea that there is a corresponding relation between quantum states and points of the complex projective space, given that the number of dimensions of the Hilbert space is finite. We check this idea through…

Mathematical Physics · Physics 2007-05-23 Bei Jia , Xi-guo Lee

We discuss a new phase space method for the computation of quantum expectation values in the high frequency regime. Instead of representing a wavefunction by its Wigner function, which typically attains negative values, we define a new…

Quantum Physics · Physics 2016-03-07 Johannes Keller , Caroline Lasser , Tomoki Ohsawa

Random matrix theory is a powerful way to describe universal correlations of eigenvalues of complex systems. It also may serve as a schematic model for disorder in quantum systems. In this review, we discuss both types of applications of…

High Energy Physics - Phenomenology · Physics 2009-10-31 J. J. M. Verbaarschot , T. Wettig

Spectral measures arise in numerous applications such as quantum mechanics, signal processing, resonances, and fluid stability. Similarly, spectral decompositions (pure point, absolutely continuous and singular continuous) often…

Spectral Theory · Mathematics 2021-03-02 Matthew John Colbrook

We present an extension of a framework for simulating single quasiparticle or collective excitations on top of strongly correlated quantum many-body ground states using infinite projected entangled pair states, a tensor network ansatz for…

Strongly Correlated Electrons · Physics 2020-05-07 Boris Ponsioen , Philippe Corboz

We develop a general theory to estimate magnetic field gradients in quantum metrology. We consider a system of $N$ particles distributed on a line whose internal degrees of freedom interact with a magnetic field. Usually gradient estimation…

Quantum Physics · Physics 2017-10-30 Sanah Altenburg , Michał Oszmaniec , Sabine Wölk , Otfried Gühne

Evolution of charged quantum fields under the action of constant nonuniform electric fields is studied. To this end we construct a special generating functional for density operators of the quantum fields with different initial conditions.…

High Energy Physics - Theory · Physics 2019-06-25 S. P. Gavrilov , D. M. Gitman , A. A. Shishmarev

The concept of phase space distribution functions and their evolution is used in the case of en enlarged phase space. In particular, we include the intrinsic spin of particles and present a quantum kinetic evolution equation for a scalar…

Quantum Physics · Physics 2015-05-18 M. Marklund , J. Zamanian , G. Brodin

We propose a novel framework for the quantum geometry of expectation values over arbitrary sets of operators and establish a link between this geometry and the eigenstates of Hamiltonian families generated by these operators. We show that…

Quantum Physics · Physics 2023-06-21 Chaoming Song

We present a spectroscopy scheme using transfer matrix and tensor network. With this method, the energy spectrum is obtained from the eigenvalues of the transfer matrix which is estimated by coarse grained tensor network of a lattice model,…

High Energy Physics - Lattice · Physics 2024-12-02 Fathiyya Izzatun Az-zahra , Shinji Takeda , Takeshi Yamazaki

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

We investigate the spectrum of differentiation matrices for certain operators on the sphere that are generated from collocation at a set of scattered points $X$ with positive definite and conditionally positive definite kernels. We focus on…

Numerical Analysis · Mathematics 2023-12-27 Thomas Hangelbroek , Christian Rieger , Grady Wright

Density matrix embedding theory (DMET) [Phys. Rev. Lett., 109, 186404 (2012)], introduced a new approach to quantum cluster embedding methods, whereby the mapping of strongly correlated bulk problems to an impurity with finite set of bath…

Strongly Correlated Electrons · Physics 2015-06-24 George H. Booth , Garnet Kin-Lic Chan

Standard projective measurements represent a subset of all possible measurements in quantum physics, defined by positive-operator-valued measures. We study what quantum measurements are projective simulable, that is, can be simulated by…

Quantum Physics · Physics 2017-11-15 Michał Oszmaniec , Leonardo Guerini , Peter Wittek , Antonio Acín

The partial trace operation is usually considered in composite quantum systems, to reduce the state on a single subsystem. This operation has a key role in the decoherence effect and quantum measurements. However, partial trace operations…

Quantum Physics · Physics 2024-03-18 Quentin Ansel

Decoherence represents a major obstacle towards realizing reliable quantum technologies. Identifying states that can be uphold against decoherence by purely coherent means, i.e., {\it stabilizable states}, for which the dissipation-induced…

Quantum Physics · Physics 2023-04-26 Tomasz Linowski , Łukasz Rudnicki , Clemens Gneiting

The Wigner-Weyl transform and phase space formulation of a density matrix approach are applied to a non-Hermitian model which is quadratic in positions and momenta. We show that in the presence of a quantum environment or reservoir, mean…

Quantum Physics · Physics 2019-10-09 Ludmila Praxmeyer , Konstantin G. Zloshchastiev

A central challenge in quantum metrology is identifying optimal measurements that saturate the quantum Cramer-Rao bound under realistic constraints, e.g., local measurements. We show that symmetries of the probe state provide a general…

Quantum Physics · Physics 2026-03-10 Jia-Xuan Liu , Hai-Long Shi , Chunfeng Wu , Sixia Yu

We use a support vector regressor based on a projected quantum kernel method to predict the density structure of 1D fermionic systems of interest in quantum chemistry and quantum matter. The kernel is built on with the observables of a…

Quantum Physics · Physics 2025-09-01 Francesco Perciavalle , Francesco Plastina , Michele Pisarra , Nicola Lo Gullo

This dissertation studies the statistics and modeling of a quantum system probed by a coherent laser field. We focus on an ensemble of qubits dispersively coupled to a traveling wave light field. The first research topic explores the…

Quantum Physics · Physics 2013-01-29 Robert L. Cook