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Quantum hypothesis testing (QHT) concerns the statistical inference of unknown quantum states. In the general setting of composite hypotheses, the goal of QHT is to determine whether an unknown quantum state belongs to one or another of two…

Quantum Physics · Physics 2025-09-01 Matteo Zecchin , Osvaldo Simeone , Aaditya Ramdas

We investigate the construction of coherent states for quantum theories of connections based on graphs embedded in a spatial manifold, as in loop quantum gravity. We discuss the many subtleties of the construction, mainly related to the…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Daniele Oriti , Roberto Pereira , Lorenzo Sindoni

Bargmann invariants, a class of gauge-invariant quantities arising from the overlaps of quantum state vectors, provide a profound and unifying framework for understanding the geometric structure of quantum mechanics. This survey offers a…

Quantum Physics · Physics 2026-01-06 Lin Zhang , Bing Xie

Exactly soluble models can serve as excellent tools to explore conceptual issues in non-perturbative quantum gravity. In perturbative approaches, it is only the two radiative modes of the linearized gravitational field that are quantized.…

General Relativity and Quantum Cosmology · Physics 2022-11-04 Abhay Ashtekar

We present a generally covariant approach to quantum mechanics in which generalized positions, momenta and time variables are treated as coordinates on a fundamental "phase-spacetime." We show that this covariant starting point makes…

High Energy Physics - Theory · Physics 2018-05-31 Gabriel Herczeg , Andrew Waldron

The discrepancy between quantum distinguishability in Hilbert space and classical distinguishability in probability space is expressed by the gap between the quantum and classical Fisher information matrices (QFIM and CFIM, respectively).…

Quantum Physics · Physics 2026-04-20 Satoya Imai , Jing Yang , Luca Pezzè

Werner and Wolf have proven in Phys. Rev. Lett. 86(16) (2001) a very elegant necessary and sufficient condition for a bosonic continuous variable bipartite Gaussian mixed quantum state to be separable. This condition is, however, difficult…

Quantum Physics · Physics 2022-10-18 Maurice de Gosson

Recently, substantial amount of activity in Quantum General Relativity (QGR) has focussed on the semiclassical analysis of the theory. In this paper we want to comment on two such developments: 1) Polymer-like states for Maxwell theory and…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Thomas Thiemann

In this paper we give a method to associate a graph with an arbitrary density matrix referred to a standard orthonormal basis in the Hilbert space of a finite dimensional quantum system. We study the related issues like classification of…

Quantum Physics · Physics 2007-08-28 Ali Saif M. Hassan , Pramod Joag

Proposals for nonlinear extenstions of quantum mechanics are discussed. Two different concepts of "mixed state" for any nonlinear version of quantum theory are introduced: (i) >genuine mixture< corresponds to operational "mixing" of…

Quantum Physics · Physics 2012-12-07 Pavel Bona

Quantum theory of field (extended) objects without a priori space-time geometry has been represented. Intrinsic coordinates in the tangent fibre bundle over complex projective Hilbert state space $CP(N-1)$ are used instead of space-time…

General Physics · Physics 2007-05-23 Peter Leifer

We introduce a geometric quantification of quantum coherence in single-mode Gaussian states and we investigate the behavior of distance measures as functions of different physical parameters. In the case of squeezed thermal states, we…

Probabilistic quantum state transformations can be characterized by the degree of state separation they provide. This, in turn, sets limits on the success rate of these transformations. We consider optimum state separation of two known pure…

Quantum Physics · Physics 2016-01-20 Emilio Bagan , Vadim Yerokhin , Andi Shehu , Edgar Feldman , Janos A. Bergou

In this paper, I will discuss the geometrical structures of multipartite quantum systems based on complex projective schemes. In particular, I will explicitly construct multi-qubit states in terms of these schemes and also discuss…

Quantum Physics · Physics 2015-05-13 Hoshang Heydari

We show that the geometry of the set of quantum states plays a crucial role in the behavior of entanglement in different physical systems. More specifically it is shown that singular points at the border of the set of unentangled states…

When a quantum pure state is drawn uniformly at random from a Hilbert space, the state is typically highly entangled. This property of a random state is known as generic entanglement of quantum states and has been long investigated from…

Quantum Physics · Physics 2020-06-23 Yoshifumi Nakata , Mio Murao

Geometric phase has been proposed as one of the promising methodologies to perform fault tolerant quantum computations. However, since decoherence plays a crucial role in such studies, understanding of mixed state geometric phase has become…

Quantum Physics · Physics 2009-11-11 Arindam Ghosh , Anil Kumar

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

Quantum complexity quantifies the difficulty of preparing a state or implementing a unitary transformation with limited resources. Applications range from quantum computation to condensed matter physics and quantum gravity. We seek to…

We propose a detailed study of the geometric entanglement properties of pure symmetric N-qubit states, focusing more particularly on the identification of symmetric states with a high geometric entanglement and how their entanglement…

Quantum Physics · Physics 2010-07-01 J. Martin , O. Giraud , P. A. Braun , D. Braun , T. Bastin
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