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We propose a generic protocol to experimentally measure the quantum metric tensor, a fundamental geometric property of quantum states. Our method is based on the observation that the excitation rate of a quantum state directly relates to…

Mesoscale and Nanoscale Physics · Physics 2018-06-20 Tomoki Ozawa , Nathan Goldman

Tensor models are measures for random tensors. They generalise matrix models and were developed to study random geometry in arbitrary dimension. Moreover, they are strongly connected to quantum gravity theories as additionally to the…

Mathematical Physics · Physics 2017-06-26 Thibault Delepouve

We introduce a new method to compute the Quantum Geometric Tensor, this procedure allows us to compute the Quantum Information Metric and the Berry curvature perturbatively for a theory with an arbitrary interaction Hamiltonian. The…

Quantum Physics · Physics 2019-04-03 J. Alvarez-Jiménez , J. David Vergara

Berry phases and the quantum-information theoretic notion of fidelity have been recently used to analyze quantum phase transitions from a geometrical perspective. In this paper we unify these two approaches showing that the underlying…

Quantum Physics · Physics 2007-12-10 Lorenzo Campos Venuti , Paolo Zanardi

The quantum geometric tensor (QGT) of a quantum system in a given parameter space captures both the geometry of the state manifold and the topology of the system. While the local QGT elements have been successfully measured in various…

Mesoscale and Nanoscale Physics · Physics 2025-08-29 Raffael L. Klees , Mónica Benito

Usually models for quantum computations deal with unitary gates on pure states. In this paper we generalize the usual model. We consider a model of quantum computations in which the state is an operator of density matrix and the gates are…

Quantum Physics · Physics 2007-05-23 Vasily E. Tarasov

Quantum criticality often lies beyond the scope of the conventional Landau paradigm, and a unifying framework has yet to emerge, due in part to the wide variety of quantum orders. We propose a geometric approach to quantum phase transitions…

Quantum Physics · Physics 2025-06-23 Chaoming Song

The quantum geometric tensor (QGT) provides nontrivial bounds among physical quantities, as exemplified by the metric-curvature inequality. In this paper, we investigate various bounds for different observables through certain…

Materials Science · Physics 2025-10-28 Koki Shinada , Naoto Nagaosa

We introduce a quantum geometric tensor in a curved space with a parameter-dependent metric, which contains the quantum metric tensor as the symmetric part and the Berry curvature corresponding to the antisymmetric part. This…

Quantum Physics · Physics 2022-09-19 Joan A. Austrich-Olivares , J. David Vergara

The notion of geometric phase has been recently introduced to analyze the quantum phase transitions of many-body systems from the geometrical perspective. In this work, we study the geometric phase of the ground state for an inhomogeneous…

Strongly Correlated Electrons · Physics 2012-09-04 Yu-Quan Ma , Shu Chen

Why do we need quantization to describe vision? What are the quadrature operators of the electromagnetic field? Is it possible to measure them? What are the characteristic functions useful for? In this brief tutorial we provide the…

Quantum Physics · Physics 2021-10-08 Stefano Olivares

We demonstrate that a geometric phase, generated via a sequence of four optomechanical interactions, can be used to increase, or generate nonlinearities in the unitary evolution of a mechanical resonator. Interactions of this form lead to…

Quantum Physics · Physics 2013-08-20 K. E. Khosla , M. R. Vanner , W. P. Bowen , G. J. Milburn

This paper is concerned with exponential moments of integral-of-quadratic functions of quantum processes with canonical commutation relations of position-momentum type. Such quadratic-exponential functionals (QEFs) arise as robust…

Quantum Physics · Physics 2021-03-18 Igor G. Vladimirov , Ian R. Petersen , Matthew R. James

The ``problem of time'' has been a pressing issue in quantum gravity for some time. To help understand this problem, Rovelli proposed a model of a two harmonic oscillators system where one of the oscillators can be thought of as a ``clock''…

Quantum Physics · Physics 2009-10-30 M. C. Ashworth

Geometric phases, arising from cyclic evolutions in a curved parameter space, appear in a wealth of physical settings. Recently, and largely motivated by the need of an experimentally realistic definition for quantum computing applications,…

Quantum Physics · Physics 2011-02-04 F. M. Cucchietti , J. -F. Zhang , F. C. Lombardo , P. I. Villar , R. Laflamme

Quantum algorithms for diverse problems, including search and optimization problems, require the implementation of a reflection operator over a target state. Commonly, such reflections are approximately implemented using phase estimation.…

Quantum Physics · Physics 2018-03-08 Anirban Narayan Chowdhury , Yigit Subasi , Rolando D. Somma

Time-dependent $\mathcal{PT}$-symmetric quantum mechanics is featured by a varying inner-product metric and has stimulated a number of interesting studies beyond conventional quantum mechanics. In this paper, we explore geometric aspects of…

Quantum Physics · Physics 2018-11-13 Da-Jian Zhang , Qing-hai Wang , Jiangbin Gong

We consider correlation functions of operators and the operator product expansion in two-dimensional quantum gravity. First we introduce correlation functions with geodesic distances between operators kept fixed. Next by making two of the…

High Energy Physics - Theory · Physics 2008-02-03 H. Aoki , H. Kawai , J. Nishimura , A. Tsuchiya

We investigate the finite-size scaling of the boundary quantum geometric tensor (QGT) numerically close to the Anderson localization transition in the presence of small external magnetic fields. The QGT exhibits universal scaling and…

Disordered Systems and Neural Networks · Physics 2019-03-27 Miklós Antal Werner , Arne Brataas , Felix von Oppen , Gergely Zaránd

A problem of finding stationary states of open quantum systems is addressed. We focus our attention on a generic type of open system: a qubit coupled to its environment. We apply the theory of block operator matrices and find stationary…

Quantum Physics · Physics 2011-05-11 Bartlomiej Gardas , Zbigniew Puchala