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Inspired by special and general relativistic systems that can have Hamiltonians involving square roots, or more general fractional powers, in this article we address the question how a suitable set of coherent states for such systems can be…

General Relativity and Quantum Cosmology · Physics 2021-11-18 Kristina Giesel , Almut Vetter

Vector coherent states (VCS) viewed as a generalization of ordinary coherent states for higher rank tensor Hilbert spaces are investigated. We consider a systematic way of generating classes of VCS which are solvable (i.e., in the present…

Mathematical Physics · Physics 2011-09-21 I. Aremua , J. Ben Geloun , M. N. Hounkonnou

Quantum circuit complexity has played a central role in recent advances in holography and many-body physics. Within quantum field theory, it has typically been studied in a Lorentzian (real-time) framework. In a departure from standard…

High Energy Physics - Theory · Physics 2022-10-12 Josiah Couch , Yale Fan , Sanjit Shashi

For quantum many-body systems in one dimension, computational complexity theory reveals that the evaluation of ground-state energy remains elusive on quantum computers, contrasting the existence of a classical algorithm for temperatures…

Statistical Mechanics · Physics 2024-06-11 Atsushi Iwaki , Chisa Hotta

Computing Gaussian ground states via variational optimization is challenging because the covariance matrices must satisfy the uncertainty principle, rendering constrained or Riemannian optimization costly, delicate, and thus difficult to…

Quantum Physics · Physics 2026-01-29 Christopher Willby , Tomohiro Hashizume , Jason Crain , Dieter Jaksch

In this study, we explore a form of quantum circuit complexity that extends to open systems. To illustrate our methodology, we focus on a basic model where the projective Hilbert space of states is depicted by the set of orientations in the…

Quantum Physics · Physics 2024-10-07 E. M. F. Curado , S. Faci , J. P. Gazeau , T. Koide , A. C. Maioli , D. Noguera

We consider Gaussian quantum circuits supplemented with non-Gaussian input states and derive sufficient conditions for efficient classical strong simulation of these circuits. In particular, we generalise the stellar representation of…

Quantum Physics · Physics 2021-07-14 Ulysse Chabaud , Giulia Ferrini , Frédéric Grosshans , Damian Markham

Simulating the nonequilibrium dynamics of thermal states is a fundamental problem across scales from high energy to condensed matter physics. Quantum computers may provide a way to solve this problem efficiently. Preparing a thermal state…

Quantum Physics · Physics 2023-11-03 Jason Saroni , Henry Lamm , Peter P. Orth , Thomas Iadecola

We study the behavior of infinite systems of coupled harmonic oscillators as t->infinity, and generalize the Central Limit Theorem (CLT) to show that their reduced Wigner distributions become Gaussian under quite general conditions. This…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Max Tegmark , Harold S. Shapiro

It is by now well-known that ground states of gapped one-dimensional (1d) quantum-many body systems with short-range interactions can be studied efficiently using classical computers and matrix product state techniques. A corresponding…

Quantum Physics · Physics 2017-08-31 Thomas Barthel

According to the pioneering work of Nielsen and collaborators, the length of the minimal geodesic in a geometric realization of a suitable operator space provides a measure of the quantum complexity of an operation. Compared with the…

Quantum Physics · Physics 2024-10-10 Satyaki Chowdhury , Martin Bojowald , Jakub Mielczarek

We examine the problem of state transformations in the framework of Gaussian thermal resource theory in the presence of catalysts. To this end, we introduce an expedient parametrisation of covariance matrices in terms of principal mode…

Quantum Physics · Physics 2022-08-10 Benjamin Yadin , Hyejung H. Jee , Carlo Sparaciari , Gerardo Adesso , Alessio Serafini

In this work, we perform a careful study of an special arrangement of coupled systems that consists of two external harmonic oscillators weakly coupled to an arbitrary network (data bus) of strongly interacting oscillators. Our aim is to…

Quantum Physics · Physics 2016-08-25 F. Nicacio , F. L. Semião

In this article we further investigate the construction of graph coherent states, first introduced in [1], in the context of loop quantum gravity. We specifically investigate the possibility of defining a family of graph coherent states…

General Relativity and Quantum Cosmology · Physics 2020-07-01 Mehdi Assanioussi

A quantal system in an eigenstate, of operators with a continuous nondegenerate eigenvalue spectrum, slowly transported round a circuit C by varing parameters in its Hamiltonian, will acquire a generalized geometrical phase factor. An…

Quantum Physics · Physics 2009-11-13 M. Maamache , Y. Saadi

We study nonchiral wave functions for systems with continuous spins obtained from the conformal field theory (CFT) of a free, massless boson. In contrast to the case of discrete spins, these can be treated as bosonic Gaussian states, which…

Strongly Correlated Electrons · Physics 2018-10-01 Benedikt Herwerth , Germán Sierra , J. Ignacio Cirac , Anne E. B. Nielsen

In this paper, we investigate a thermal coherent state defined with the Lie-Trotter product formula under the formalism of the thermo field dynamics. In the definition of our thermal coherent state, we treat the thermalizing operator and…

Quantum Physics · Physics 2015-07-14 Hiroo Azuma , Masashi Ban

We define circuits given by unitary representations of Lorentzian conformal field theory in 3 and 4 dimensions. Our circuits start from a spinning primary state, allowing us to generalize formulas for the circuit complexity obtained from…

High Energy Physics - Theory · Physics 2021-12-22 Robert de Mello Koch , Minkyoo Kim , Hendrik J. R. Van Zyl

In this paper, we developed an algebraic formulation for the generalized thermal coherent states with a Thermofield Dynamics approach for multi-modes, based on coset space of Lie groups. In particular, we applied our construction on $SU(2)$…

Mathematical Physics · Physics 2017-01-18 S. Floquet , M. A. S. Trindade , J. D. M. Vianna

Motivated by the holographic complexity proposals, in this paper, we investigate the time dependence of the complexity for the Fermionic thermofield double state (TFD) using the Nielsen approach and Fubini-Study (FS) approach separately. In…

High Energy Physics - Theory · Physics 2019-01-18 Jie Jiang , Xiangjing Liu