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Related papers: Pseudoentanglement Ain't Cheap

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A general inequality between entanglement entropy and a number of topologically ordered states is derived, even without using the properties of the parent Hamiltonian or the formalism of topological quantum field theory. Given a quantum…

Quantum Physics · Physics 2013-10-03 Isaac H. Kim

The degree of entanglement is determined for an arbitrary state of a broad class of PT-symmetric bipartite composite systems. Subsequently we quantify the rate with which entangled states are generated and show that this rate can be…

High Energy Physics - Theory · Physics 2013-05-23 Christian Zielinski , Qing-hai Wang

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

Quantum entanglement is a crucial resource for learning properties from nature, but a precise characterization of its advantage can be challenging. In this work, we consider learning algorithms without entanglement to be those that only…

Quantum Physics · Physics 2024-10-21 Senrui Chen , Changhun Oh , Sisi Zhou , Hsin-Yuan Huang , Liang Jiang

The efficient generation of random quantum states is a long-standing challenge, motivated by their diverse applications in quantum information processing tasks. In this work, we identify entanglement as the key resource that enables local…

Quantum Physics · Physics 2026-01-26 Wonjun Lee , Hyukjoon Kwon , Gil Young Cho

We give a pair of algorithms that efficiently learn a quantum state prepared by Clifford gates and $O(\log n)$ non-Clifford gates. Specifically, for an $n$-qubit state $|\psi\rangle$ prepared with at most $t$ non-Clifford gates, our…

Quantum Physics · Physics 2025-11-07 Sabee Grewal , Vishnu Iyer , William Kretschmer , Daniel Liang

Entangled quantum states share properties that do not have classical analogs, in particular, they show correlations that can violate Bell inequalities. It is therefore an interesting question to see what happens to entanglement measures --…

Quantum Physics · Physics 2022-03-08 Giuseppe Mussardo , Jacopo Viti

Bell-network states are loop-quantum-gravity states that glue quantum polyhedra with entanglement. We present an algorithm and a code that evaluates the reduced density matrix of a Bell-network state and computes its entanglement entropy.…

General Relativity and Quantum Cosmology · Physics 2019-04-24 Eugenio Bianchi , Pietro Dona , Ilya Vilensky

We study the entanglement properties of randomized mixed hypergraph states, extending the concept of randomized mixed graph states to encompass hypergraph-based quantum states. In our model, imperfect generalized multi-qubit gates are…

Quantum Physics · Physics 2026-04-13 Vinícius Salem , Alison A. Silva , Fabiano M. Andrade

The generation of a large amount of entanglement is a necessary condition for a quantum computer to achieve quantum advantage. In this paper, we propose a method to efficiently generate pseudo-random quantum states, for which the degree of…

Quantum Physics · Physics 2023-04-05 Gabriele Cenedese , Maria Bondani , Dario Rosa , Giuliano Benenti

We propose an efficient protocol to estimate the fidelity of an $n$-qubit entangled measurement device, requiring only qubit state preparations and classical data post-processing. It works by measuring the eigenstates of Pauli operators,…

Quantum Physics · Physics 2023-12-22 Zanqiu Shen , Kun Wang

Quantum informatic quantities such as entanglement entropy are useful in detecting quantum phase transitions. Recently, a new entanglement measure called pseudo-entropy was proposed which is a generalization of the more well-known…

High Energy Physics - Theory · Physics 2025-09-23 Song He , Pak Hang Chris Lau , Long Zhao

In this article, we explore properties of pseudo entropy [1] in quantum field theories and spin systems from several approaches. Pseudo entropy is a generalization of entanglement entropy such that it depends on both an initial and final…

High Energy Physics - Theory · Physics 2021-09-22 Ali Mollabashi , Noburo Shiba , Tadashi Takayanagi , Kotaro Tamaoka , Zixia Wei

We present a quantum algorithm to compute the entanglement spectrum of arbitrary quantum states. The interesting universal part of the entanglement spectrum is typically contained in the largest eigenvalues of the density matrix which can…

Strongly Correlated Electrons · Physics 2017-11-29 Sonika Johri , Damian S. Steiger , Matthias Troyer

Notions of nonstabilizerness, or "magic", quantify how non-classical quantum states are in a precise sense: states exhibiting low nonstabilizerness preclude quantum advantage. We introduce 'pseudomagic' ensembles of quantum states that,…

Quantum Physics · Physics 2024-05-31 Andi Gu , Lorenzo Leone , Soumik Ghosh , Jens Eisert , Susanne Yelin , Yihui Quek

There are many possible architectures of qubit connectivity that designers of future quantum computers will need to choose between. However, the process of evaluating a particular connectivity graph's performance as a quantum architecture…

We study experimentally accessible lower bounds on entanglement measures based on entropic uncertainty relations. Experimentally quantifying entanglement is highly desired for applications of quantum simulation experiments to fundamental…

Quantum Physics · Physics 2021-05-25 Bjarne Bergh , Martin Gärttner

Quantum entropy is an important measure for describing the uncertainty of a quantum state, more uncertainty in subsystems implies stronger quantum entanglement between subsystems. Our goal in this work is to quantify bipartite entanglement…

Quantum Physics · Physics 2022-04-18 Xue Yang , Yan-Han Yang , Li-Ming Zhao , Ming-Xing Luo

Quantum states are the key mathematical objects in quantum mechanics, and entanglement lies at the heart of the nascent fields of quantum information processing and computation. However, there has not been a general, necessary and…

Quantum Physics · Physics 2024-10-10 Bang-Hai Wang

We perform optimal-control-theory calculations to determine the minimum number of two-qubit CNOT gates needed to perform quantum state preparation and unitary operator synthesis for few-qubit systems. By considering all possible gate…

Quantum Physics · Physics 2022-08-24 Sahel Ashhab , Naoki Yamamoto , Fumiki Yoshihara , Kouichi Semba