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Proposed models of closed timelike curves (CTCs) have been shown to enable powerful information-processing protocols. We examine the simulation of models of CTCs both by other models of CTCs and by physical systems without access to CTCs.…

Quantum Physics · Physics 2017-02-28 Todd A. Brun , Mark M. Wilde

The study of topologically ordered states have given rise to a growing interest in symmetry protected states in quantum matter. Recently, this theory has been extended to quantum many body systems which demonstrate ordered states at low…

Mesoscale and Nanoscale Physics · Physics 2023-04-04 Christopher Sims

We study the paradoxical aspects of closed time-like curves and their impact on the theory of computation. After introducing the $\text{TM}_\text{CTC}$, a classical Turing machine benefiting CTCs for backward time travel, Aaronson et al.…

Computational Complexity · Computer Science 2023-01-30 Sara Babaee Khanehsar , Farzad Didehvar

Quantum many-body systems display rich phase structure in their low-temperature equilibrium states. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit…

Quantum Physics · Physics 2022-02-10 Xiao Mi , Matteo Ippoliti , Chris Quintana , Ami Greene , Zijun Chen , Jonathan Gross , Frank Arute , Kunal Arya , Juan Atalaya , Ryan Babbush , Joseph C. Bardin , Joao Basso , Andreas Bengtsson , Alexander Bilmes , Alexandre Bourassa , Leon Brill , Michael Broughton , Bob B. Buckley , David A. Buell , Brian Burkett , Nicholas Bushnell , Benjamin Chiaro , Roberto Collins , William Courtney , Dripto Debroy , Sean Demura , Alan R. Derk , Andrew Dunsworth , Daniel Eppens , Catherine Erickson , Edward Farhi , Austin G. Fowler , Brooks Foxen , Craig Gidney , Marissa Giustina , Matthew P. Harrigan , Sean D. Harrington , Jeremy Hilton , Alan Ho , Sabrina Hong , Trent Huang , Ashley Huff , William J. Huggins , L. B. Ioffe , Sergei V. Isakov , Justin Iveland , Evan Jeffrey , Zhang Jiang , Cody Jones , Dvir Kafri , Tanuj Khattar , Seon Kim , Alexei Kitaev , Paul V. Klimov , Alexander N. Korotkov , Fedor Kostritsa , David Landhuis , Pavel Laptev , Joonho Lee , Kenny Lee , Aditya Locharla , Erik Lucero , Orion Martin , Jarrod R. McClean , Trevor McCourt , Matt McEwen , Kevin C. Miao , Masoud Mohseni , Shirin Montazeri , Wojciech Mruczkiewicz , Ofer Naaman , Matthew Neeley , Charles Neill , Michael Newman , Murphy Yuezhen Niu , Thomas E. O\' Brien , Alex Opremcak , Eric Ostby , Balint Pato , Andre Petukhov , Nicholas C. Rubin , Daniel Sank , Kevin J. Satzinger , Vladimir Shvarts , Yuan Su , Doug Strain , Marco Szalay , Matthew D. Trevithick , Benjamin Villalonga , Theodore White , Z. Jamie Yao , Ping Yeh , Juhwan Yoo , Adam Zalcman , Hartmut Neven , Sergio Boixo , Vadim Smelyanskiy , Anthony Megrant , Julian Kelly , Yu Chen , S. L. Sondhi , Roderich Moessner , Kostyantyn Kechedzhi , Vedika Khemani , Pedram Roushan

In this work we have explored few tools in Quantum State Tomography for Continuous Variable Systems. The concept of quantum states in phase space representation is introduced in a simple manner by using a few statistical concepts. Unlike…

Quantum Physics · Physics 2019-12-12 Ludmila Botelho

We examine some variants of computation with closed timelike curves (CTCs), where various restrictions are imposed on the memory of the computer, and the information carrying capacity and range of the CTC. We give full characterizations of…

Computational Complexity · Computer Science 2014-01-29 A. C. Cem Say , Abuzer Yakaryilmaz

The possible existence of closed timelike curves (CTCs) draws attention to fundamental questions about what is physically possible and what is not. An example is the "no cloning theorem" in quantum mechanics, which states that no physical…

Quantum Physics · Physics 2015-06-19 D. Ahn , T. C. Ralph , R. B. Mann

We study the nature of entanglement in presence of Deutschian closed timelike curves (D-CTCs) and we observe that qubits traveling along a D-CTC allow unambiguous discrimination of Bell states with Local Operations and Classical…

Quantum Physics · Physics 2022-10-20 Subhayan Roy Moulick , Prasanta K. Panigrahi

We study the power of closed timelike curves (CTCs) and other nonlinear extensions of quantum mechanics for distinguishing nonorthogonal states and speeding up hard computations. If a CTC-assisted computer is presented with a labeled…

Quantum Physics · Physics 2009-10-29 Charles H. Bennett , Debbie Leung , Graeme Smith , John A. Smolin

The possible existence of closed timelike curves (CTCs) draws attention to fundamental questions about what is physically possible and what is not. An example is the "no cloning theorem" in quantum mechanics, which states that no physical…

Quantum Physics · Physics 2015-06-05 D. Ahn , C. R. Myers , T. C. Ralph , R. B. Mann

Quantum state tomography is a fundamental tool in quantum information processing. It allows us to estimate the state of a quantum system by measuring different observables on many identically prepared copies of the system. This is, in…

Quantum Physics · Physics 2011-11-28 Carlos A. Riofrío

Prethermal discrete time crystals (PDTCs) are a nonequilibrium state of matter characterized by long-range spatiotemporal order, and exhibiting a subharmonic response stabilized by many-body interactions under periodic driving. The inherent…

While closed timelike curves (CTCs) are not known to exist, studying their consequences has led to nontrivial insights in general relativity, quantum information, and other areas. In this paper we show that if CTCs existed, then quantum…

Quantum Physics · Physics 2009-11-13 Scott Aaronson , John Watrous

Recently, there has been much interest in the evolution of quantum particles on closed time-like curves (CTCs). However, such models typically assume point-like particles with only two degrees of freedom - a very questionable assumption…

General Relativity and Quantum Cosmology · Physics 2012-09-18 J. L. Pienaar , C. R. Myers , T. C. Ralph

A ring resonator involves a scattering process where a part of the output is fed again into the input. The same formal structure is encountered in the problem of time travel in a neighborhood of a closed timelike curve (CTC). We know how to…

Quantum Physics · Physics 2022-07-19 Marek Czachor

The discrete time crystal (DTC) is a recently discovered phase of matter that spontaneously breaks time-translation symmetry. Disorder-induced many-body-localization is required to stabilize a DTC to arbitrary times, yet an experimental…

Generalized quantum mechanics is used to examine a simple two-particle scattering experiment in which there is a bounded region of closed timelike curves (CTCs) in the experiment's future. The transitional probability is shown to depend on…

High Energy Physics - Theory · Physics 2009-10-30 Seth Rosenberg

Understanding the relationship between the time-symmetric nature of physical laws and the apparent directionality of causality is a central question in quantum foundations. The standard operational formulation, widely used in quantum…

Quantum Physics · Physics 2025-08-05 Eliot Jean , Ralph Silva , V. Vilasini

Standard one-way quantum computers (1WQC) combine time symmetric unitary evolution, with asymmetric treatment of boundaries: state preparation allows to enforce a chosen initial state, however, for the final state measurement chooses a…

General Physics · Physics 2023-08-30 Jarek Duda

Quantum tomography is a cornerstone of quantum information science, enabling the reconstruction of states and channels from experimental data. Here we introduce a new paradigm, temporal state tomography (TST), for reconstructing quantum…

Quantum Physics · Physics 2026-05-05 Zhian Jia