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Quantum Field Theory (QFT) represents a vast generalization of Quantum Mechanics (QM), as it deals with systems that have an infinite number of degrees of freedom. The Stone-von Neumann theorem, which establishes the equivalence of…

Mathematical Physics · Physics 2023-07-13 Ahmed Halawani

Entropy is one of the most basic concepts in thermodynamics and statistical mechanics. The most widely used definition of statistical mechanical entropy for a quantum system is introduced by von Neumann. While in classical systems, the…

Quantum Physics · Physics 2020-03-18 Tian Qiu , Zhaoyu Fei , Rui Pan , Haitao Quan

We introduce a novel method for computing entanglement entropy across surfaces in Loop Quantum Gravity by employing techniques from quantum error correcting codes. In this construction, the redundancy encoded in the gauge invariant subspace…

General Relativity and Quantum Cosmology · Physics 2025-11-03 Sean Tobin

Entropy is a measure of the randomness of a system. Estimating the entropy of a quantum state is a basic problem in quantum information. In this paper, we introduce a time-efficient quantum approach to estimating the von Neumann entropy…

Quantum Physics · Physics 2025-12-02 Qisheng Wang , Zhicheng Zhang

Due to the linearity of quantum operations, it is not straightforward to implement nonlinear transformations on a quantum computer, making some practical tasks like a neural network hard to be achieved. In this work, we define a task called…

Quantum Physics · Physics 2024-05-20 Naixu Guo , Kosuke Mitarai , Keisuke Fujii

Some quantum algorithms have "quantum speedups": improved time complexity as compared with the best-known classical algorithms for solving the same tasks. Can we understand what fuels these speedups from an entropic perspective? Information…

Quantum Physics · Physics 2024-11-07 Jason Pollack , Dylan VanAllen

We introduce and systematically develop the theory of \emph{quantum doubly stochastic operators}, i.e. positive, trace-preserving maps on non-commutative $L_p$-spaces associated to semifinite von Neumann algebras. After establishing basic…

Operator Algebras · Mathematics 2026-05-19 Emma Sulaver

We show how to compute the purity and entanglement entropy for quantum fields in a systematic perturbative expansion. To that end, we generalize the in-in formalism to non-unitary dynamics (i.e. accounting for the presence of an…

High Energy Physics - Theory · Physics 2024-08-29 Thomas Colas , Julien Grain , Greg Kaplanek , Vincent Vennin

The operational structure of quantum couplings and entanglements is studied and classified for semifinite von Neumann algebras. We show that the classical-quantum correspondences such as quantum encodings can be treated as diagonal…

Quantum Physics · Physics 2009-11-07 V. P. Belavkin , M. Ohya

Nonlinear spectroscopy is a cornerstone of quantum science, providing unique access to multi-point correlations, quantum coherence, and couplings that are invisible to linear methods. However, classical simulation of these phenomena is…

Quantum Physics · Physics 2026-04-20 Long Xiong , Xiaoyang Wang , Xiaoxia Cai , Xiao Yuan

Many important properties of quantum channels are quantified by means of entropic functionals. Characteristics of such a kind are closely related to different representations of a quantum channel. In the Jamio{\l}kowski-Choi representation,…

Quantum Physics · Physics 2013-07-23 Alexey E. Rastegin

Quantum computation has been growing rapidly in both theory and experiments. In particular, quantum computing devices with a large number of qubits have been developed by IBM, Google, IonQ, and others. The current quantum computing devices…

Quantum Physics · Physics 2021-02-10 Rishabh Gupta , Rongxin Xia , Raphael D. Levine , Sabre Kais

A new axiomatic characterization with a minimum of conditions for entropy as a function on the set of states in quantum mechanics is presented. Traditionally unspoken assumptions are unveiled and replaced by proven consequences of the…

Mathematical Physics · Physics 2014-07-02 Bernhard Baumgartner

A large class of strongly correlated quantum systems can be described in certain large-N limits by quadratic in field actions along with self-consistency equations that determine the two-point functions. We use the replica approach and the…

Strongly Correlated Electrons · Physics 2024-02-20 Siqi Shao , Yashar Komijani

We consider properties of quantum channels with use of unified entropies. Extremal unravelings of quantum channel with respect to these entropies are examined. The concept of map entropy is extended in terms of the unified entropies. The…

Quantum Physics · Physics 2015-05-30 Alexey E. Rastegin

Pseudo entropy is an interesting quantity with a simple gravity dual, which generalizes entanglement entropy such that it depends on both an initial and a final state. Here we reveal the basic properties of pseudo entropy in quantum field…

High Energy Physics - Theory · Physics 2021-03-03 Ali Mollabashi , Noburo Shiba , Tadashi Takayanagi , Kotaro Tamaoka , Zixia Wei

In this Thesis, several results in quantum information theory are collected, most of which use entropy as the main mathematical tool. *While a direct generalization of the Shannon entropy to density matrices, the von Neumann entropy behaves…

Quantum Physics · Physics 2018-10-25 Christian Majenz

This paper introduces a novel approach to implementing non-unitary linear transformations of basis on quantum computational platforms, a significant leap beyond the conventional unitary methods. By integrating Singular Value Decomposition…

Quantum Physics · Physics 2025-02-14 Guorui Zhu , Joel Bierman , Jianfeng Lu , Yingzhou Li

In the rapidly evolving field of quantum computing, quantifying circuit complexity remains a critical challenge. This paper introduces Character Complexity, a novel measure that bridges Group-theoretic concepts with practical quantum…

Quantum Physics · Physics 2024-09-19 Daksh Shami

Humor recognition has been extensively studied with different methods in the past years. However, existing studies on humor recognition do not understand the mechanisms that generate humor. In this paper, inspired by the incongruity theory,…

Computation and Language · Computer Science 2023-02-09 Yang Liu , Yuexian Hou