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We study the fermionic non-Gaussianity in typical quantum states, focusing on Haar random states of qubits with or without a global $U(1)$ symmetry. Using the Weingarten calculus, we derive analytical predictions for the non-Gaussianity,…

Statistical Mechanics · Physics 2026-05-20 Filiberto Ares , Sara Murciano , Pasquale Calabrese

The Fubini-Study metric is a central element of information geometry. We explore the role played by information geometry for determining the circuit complexity of Virasoro circuits and their deformations. To this effect, we study unitary…

High Energy Physics - Theory · Physics 2025-05-21 Johanna Erdmenger , Jani Kastikainen , Tim Schuhmann

Non-Hermitian systems exhibit spectral and topological phenomena absent in Hermitian physics; however, their geometric characterization is hindered by an intrinsic ambiguity rooted in the eigenspace of non-Hermitian Hamiltonians, which…

Quantum Physics · Physics 2026-04-06 Ievgen I. Arkhipov

To explore the properties of space and initial singularities in the context of general relativity, where spacetime becomes poorly defined and no longer belongs to a regular manifold, we examine the evolution of the expansion of timelike…

General Relativity and Quantum Cosmology · Physics 2025-04-04 Abdel Nasser Tawfik , Azzah A. Alshehri , Antonio Pasqua

Topological physics has broadened its scope from the study of topological insulating phases to include nodal phases containing band structure singularities. The geometry of the corresponding quantum states is described by the quantum metric…

In order to resolve the measurement problem of Quantum Mechanics, non-unitary time evolution has been derived from the unitarity of standard quantum formalism. New wave functions of free and non-free quantum systems follow from Schroedinger…

Quantum Physics · Physics 2007-05-23 Pradip Kumar Chatterjee

In this article, we examine the behavior of the Riemannian and Hermitian curvature tensors of a Hermitian metric, when one of the curvature tensors obeys all the symmetry conditions of the curvature tensor of a K\"ahler metric. We will call…

Differential Geometry · Mathematics 2023-03-31 Bo Yang , Fangyang Zheng

The Fisher-Rao (FR) information matrix is a central object in multiparameter quantum estimation theory. The geometry of a quantum state can be envisaged through the Riemannian manifold generated by the FR-metric corresponding to the quantum…

Quantum Physics · Physics 2025-09-30 Shilpa Nandi , Shatarupa Maity , Pinaki Patra

While phases and phase transitions are conventionally described by local order parameters in real space, we present a unified framework characterizing the phase transition through the geometry of configuration space defined by the…

Statistical Mechanics · Physics 2026-05-21 Yu-Jing Liu , Wen-Yu Su , Yong-Feng Yang , Nvsen Ma , Chen Cheng

A series of geometric concepts are formulated for $\mathcal{PT}$-symmetric quantum mechanics and they are further unified into one entity, i.e., an extended quantum geometric tensor (QGT). The imaginary part of the extended QGT gives a…

Quantum Physics · Physics 2019-04-10 Da-Jian Zhang , Qing-hai Wang , Jiangbin Gong

Recently, much research has been carried out on Hamiltonians that are not Hermitian but are symmetric under space-time reflection, that is, Hamiltonians that exhibit PT symmetry. Investigations of the Sturm-Liouville eigenvalue problem…

High Energy Physics - Theory · Physics 2007-05-23 Carl M. Bender , Dorje C. Brody , Lane P. Hughston , Bernhard K. Meister

The description of a closed quantum system is extended with the identification of an underlying substructure enabling an expanded formulation of dynamics in the Heisenberg picture. Between measurements a ``state point" moves in an…

Quantum Physics · Physics 2026-01-21 Anthony John Bracken

Unitarity is a cornerstone of quantum theory, ensuring the conservation of probability and information. Although non-Hermitian Hamiltonians are typically associated with open or dissipative systems, pseudo-Hermitian quantum mechanics shows…

High Energy Physics - Theory · Physics 2025-11-03 Ruifeng Leng , Cheng-Yang Lee , Siyi Zhou

Hilbert space combines the properties of two fundamentally different types of mathematical spaces: vector space and metric space. While the vector-space aspects of Hilbert space, such as formation of linear combinations of state vectors,…

Quantum Physics · Physics 2015-05-27 I. D'Amico , J. P. Coe , V. V. Franca , K. Capelle

In the conventional Schr\"{o}dinger's formulation of quantum mechanics the unitary evolution of a state $\psi$ is controlled, in Hilbert space ${\cal L}$, by a Hamiltonian $\mathfrak{h}$ which must be self-adjoint. In the recent,…

Quantum Physics · Physics 2023-12-21 Olaf Lechtenfeld , Miloslav Znojil

A generalized Noether's theorem and the operational determination of a physical geometry in quantum physics are used to motivate a quantum geometry consisting of relations between quantum states that are defined by a universal group. Making…

Quantum Physics · Physics 2007-05-23 Jeeva Anandan

For (2+2)-dimensional nonholonomic distributions, the physical information contained into a spacetime (pseudo) Riemannian metric can be encoded equivalently into new types of geometric structures and linear connections constructed as…

General Relativity and Quantum Cosmology · Physics 2010-04-08 Sergiu I. Vacaru

Any set of pure states living in an given Hilbert space possesses a natural and unique metric --the Haar measure-- on the group $U(N)$ of unitary matrices. However, there is no specific measure induced on the set of eigenvalues $\Delta$ of…

Quantum Physics · Physics 2015-06-18 J. Batle

We propose an approach to the study of open quantum systems based on a parametric representation of the principal system. The representation is obtained introducing generalized coherent states for the environment, and is such that the…

Quantum Physics · Physics 2013-12-12 Dario Calvani , Alessandro Cuccoli , Nikitas Gidopoulos , Paola Verrucchi

This thesis explores the application of differential geometric and general relativistic techniques to deepen our understanding of quantum mechanical systems. We focus on three systems, employing these mathematical frameworks to uncover…

High Energy Physics - Theory · Physics 2025-02-19 Aonghus Hunter-McCabe , Brian P. Dolan , Peter Coles