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The application of geometry to physics has provided us with new insightful information about many physical theories such as classical mechanics, general relativity, and quantum geometry (quantum gravity). The geometry also plays an…

Quantum Physics · Physics 2015-06-19 Hoshang Heydari

The properties which give quantum mechanics its unique character - unitarity, complementarity, non-commutativity, uncertainty, nonlocality - derive from the algebraic structure of Hermitian operators acting on the wavefunction in complex…

Quantum Physics · Physics 2022-09-14 Tim Palmer

Quantum information processing faces a significant hurdle: noise. Different noise sources induce varying errors in quantum operations depending on the underlying dynamics. To gain a deeper understanding of these error mechanisms, we…

Quantum Physics · Physics 2025-05-02 Yong-Ju Hai , Junning Li , Junkai Zeng , Xiu-Hao Deng

For any quantum algorithm given by a path in the space of unitary operators we define the computational complexity as the typical computational time associated with the path. This time is defined using a quantum time estimator associated…

High Energy Physics - Theory · Physics 2020-04-01 Cesar Gomez

Loop Quantum Gravity faces challenges in constructing a well-defined Hamiltonian constraint and understanding the quantum notion of time. In this paper these issues are studied by quantizing the $U(1)^3$ model, a simplified system…

General Relativity and Quantum Cosmology · Physics 2024-12-02 Sepideh Bakhoda , Yongge Ma

The concept of quantum complexity has far-reaching implications spanning theoretical computer science, quantum many-body physics, and high energy physics. The quantum complexity of a unitary transformation or quantum state is defined as the…

High Energy Physics - Theory · Physics 2021-08-02 Fernando G. S. L. Brandão , Wissam Chemissany , Nicholas Hunter-Jones , Richard Kueng , John Preskill

We develop a unified quantum geometric framework to understand reactive quantum dynamics. The critical roles of the quantum geometry of adiabatic electronic states in both adiabatic and non-adiabatic quantum dynamics are unveiled. A…

Chemical Physics · Physics 2025-05-19 Yujuan Xie , Ruoxi Liu , Bing Gu

We introduce a framework that allows for the exact analytic treatment of quantum dynamics subject to coherent noise. The noise is modeled via unitary evolution under a Hamiltonian drawn from a random-matrix ensemble for arbitrary…

Quantum Physics · Physics 2024-10-11 Mert Okyay , Oliver Hart , Rahul Nandkishore , Aaron J. Friedman

Understanding out-of-equilibrium quantum dynamics is a critical outstanding problem, with key questions regarding characterizing adiabaticity for applications in quantum technologies. We show how the metric-space approach to quantum…

Quantum Physics · Physics 2018-07-11 A. H. Skelt , R. W. Godby , I. D'Amico

We consider a quaternionic quantum formalism for the description of quantum states and quantum dynamics. We prove that generalized quantum measurements on physical systems in quaternionic quantum theory can be simulated by usual quantum…

Quantum Physics · Physics 2015-07-29 Matthew A. Graydon

We propose how to compute the complexity of operators generated by Hamiltonians in quantum field theory (QFT) and quantum mechanics (QM). The Hamiltonians in QFT/QM and quantum circuit have a few essential differences, for which we…

High Energy Physics - Theory · Physics 2019-03-27 Run-Qiu Yang , Keun-Young Kim

Quantum computational complexity estimates the difficulty of constructing quantum states from elementary operations, a problem of prime importance for quantum computation. Surprisingly, this quantity can also serve to study a completely…

High Energy Physics - Theory · Physics 2022-03-02 Shira Chapman , Giuseppe Policastro

Characterization of mixed quantum states represented by density operator is one of the most important task in quantum information processing. In this work we will present a geometric approach to characterize the density operator in terms of…

Quantum Physics · Physics 2017-11-08 Hoshang Heydari

The past few years have seen a revived interest in quantum geometrical characterizations of band structures due to the rapid development of topological insulators and semi-metals. Although the metric tensor has been connected to many…

Mesoscale and Nanoscale Physics · Physics 2023-03-07 Adrien Bouhon , Abigail Timmel , Robert-Jan Slager

We formulate quantum group Riemannian geometry as a gauge theory of quantum differential forms. We first develop (and slightly generalise) classical Riemannian geometry in a self-dual manner as a principal bundle frame resolution and a dual…

q-alg · Mathematics 2008-02-03 S. Majid

The qualitatively new concept of dynamic complexity in quantum mechanics is based on a new paradigm appearing within a nonperturbational analysis of the Schroedinger equation for a generic Hamiltonian system. The unreduced analysis…

Quantum Physics · Physics 2007-05-23 Andrei P. Kirilyuk

We show that the Hilbert space spanned by a continuously parametrized wavefunction family---i.e., a quantum state manifold---is dominated by a subspace, onto which all member states have close to unity projection weight. Its characteristic…

Statistical Mechanics · Physics 2017-11-29 Zhoushen Huang , Alexander V. Balatsky

Hybrid quantum-classical algorithms are among the most promising systems to implement quantum computing under the Noisy-Intermediate Scale Quantum (NISQ) technology. In this paper, at first, we investigate a quantum dynamics algorithm for…

Quantum Physics · Physics 2020-08-13 Mahmoud Mahdian , H. Davoodi Yeganeh

Geometrical structures of quantum mechanics provide us with new insightful results about the nature of quantum theory. In this work we consider mixed quantum states represented by finite rank density operators. We review our geometrical…

Quantum Physics · Physics 2015-06-23 Hoshang Heydari , Ole Andersson

The manifold of coupling constants parametrizing a quantum Hamiltonian is equipped with a natural Riemannian metric with an operational distinguishability content. We argue that the singularities of this metric are in correspondence with…

Quantum Physics · Physics 2007-05-23 P. Zanardi , P. Giorda , M. Cozzini