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We address the issue of quantifying the non-Gaussian character of a bosonic quantum state and introduce a non-Gaussianity measure based on the Hilbert-Schmidt distance between the state under examination and a reference Gaussian state. We…

Quantum Physics · Physics 2009-11-13 Marco G. Genoni , Matteo G. A. Paris , Konrad Banaszek

Towards formulating quantum gravity, we present a novel mechanism for the emergence of spacetime geometry from randomness. In [arXiv:1705.06097], we defined for a given Markov stochastic process "the distance between configurations," which…

High Energy Physics - Theory · Physics 2020-04-03 Masafumi Fukuma , Nobuyuki Matsumoto

Quantum state tomography is an essential component of modern quantum technology. In application to continuous-variable harmonic-oscilator systems, such as the electromagnetic field, existing tomography methods typically reconstruct the…

Quantum Physics · Physics 2023-01-09 Ekaterina Fedotova , Nikolai Kuznetsov , Egor Tiunov , A. E. Ulanov , A. I. Lvovsky

The geometrical description of a Hilbert space asociated with a quantum system considers a Hermitian tensor to describe the scalar inner product of vectors which are now described by vector fields. The real part of this tensor represents a…

Mathematical Physics · Physics 2010-10-12 P. Aniello , J. Clemente-Gallardo , G. Marmo , G. F. Volkert

This paper is a contribution to the development of a framework, to be used in the context of semiclassical canonical quantum gravity, in which to frame questions about the correspondence between discrete spacetime structures at "quantum…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Luca Bombelli , Alejandro Corichi , Oliver Winkler

Great computational effort is invested in generating equilibrium states for molecular systems using, for example, Markov chain Monte Carlo. We present a probabilistic model that generates statistically independent samples for molecules from…

Machine Learning · Statistics 2021-02-09 Gregor N. C. Simm , José Miguel Hernández-Lobato

We define the quantum Wasserstein distance such that the optimization of the coupling is carried out over bipartite separable states rather than bipartite quantum states in general, and examine its properties. Surprisingly, we find that the…

Quantum Physics · Physics 2023-10-17 Géza Tóth , József Pitrik

On a Riemannian manifold with a positive lower bound on the Ricci tensor, the distance of isoperimetric sets from geodesic balls is quantitatively controlled in terms of the gap between the isoperimetric profile of the manifold and that of…

Differential Geometry · Mathematics 2020-04-22 F. Cavalletti , F. Maggi , A. Mondino

Measurement based quantum computation requires the generation of a cluster state (quantum resource) prior to starting a computation. Generation of this entangled state can be difficult with many schemes already proposed. We present an…

Quantum Physics · Physics 2015-03-17 Neil B. Lovett , Benjamin T. H. Varcoe

Combining gravity with quantum theory is still work in progress. On the one hand, classical gravity, is the geometry of space-time determined by the energy-momentum tensor of matter and the resulting nonlinear equations; on the other hand,…

Quantum Physics · Physics 2024-01-26 P. Gusin , D. Burys , A. Radosz

A generalised definition of the metric of quantum states is proposed by using the techniques of differential geometry. The metric of quantum state space derived earlier by Anandan, is reproduced and verified here by this generalised…

Quantum Physics · Physics 2007-05-23 Aalok Pandya , Ashok K. Nagawat

Quantum metrology enhances measurement precision by utilising the properties of quantum physics. In interferometry, this is typically achieved by evolving highly-entangled quantum states before performing single-shot measurements to reveal…

Quantum Physics · Physics 2023-01-11 Kawthar Al Rasbi , Almut Beige , Lewis A. Clark

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

We study how topological crystalline defects--dislocations--reshape the real-space quantum geometric tensor and act as tunable sources of quantum geometry. We show that dislocations strongly enhance the quantum metric, establishing a direct…

Mesoscale and Nanoscale Physics · Physics 2025-12-22 Carlos Saji , Roberto E. Troncoso

By applying the projector to the filled lattice eigenstates on a specific position, or applying the local electron annihilation operator on the many-body ground state, one can construct a quantum state localized around a specific position…

Mesoscale and Nanoscale Physics · Physics 2025-03-06 Lucas A. Oliveira , Wei Chen

In the first part of this review we introduce the basics theory behind geometric phases and emphasize their importance in quantum theory. The subject is presented in a general way so as to illustrate its wide applicability, but we also…

Quantum Physics · Physics 2007-05-23 Vlatko Vedral

Quantum computers hold great promise, but it remains a challenge to find efficient quantum circuits that solve interesting computational problems. We show that finding optimal quantum circuits is essentially equivalent to finding the…

Quantum Physics · Physics 2009-11-13 Michael A. Nielsen , Mark R. Dowling , Mile Gu , Andrew C. Doherty

Geometry and topology are fundamental concepts, which underlie a wide range of fascinating physical phenomena such as topological states of matter and topological defects. In quantum mechanics, the geometry of quantum states is fully…

For many materials, a precise knowledge of their dispersion spectra is insufficient to predict their ordered phases and physical responses. Instead, these materials are classified by the geometrical and topological properties of their…

Materials Science · Physics 2021-06-16 Qiong Ma , Adolfo G. Grushin , Kenneth S. Burch

Extracting meaningful information about unknown quantum states without performing a full tomography is an important task. Low-dimensional projections and random measurements can provide such insight but typically require careful crafting.…