Optical time travel: proposal for testing Hawking’s chronology protection conjecture in an optical analogue

David Bermudez; Ulf Leonhardt

doi:10.1088/1361-6382/ae88aa

Optical time travel: proposal for testing Hawking’s chronology protection conjecture in an optical analogue

David Bermudez
, Ulf Leonhardt

Department of Physics of Complex Systems

Weizmann Institute of Science

Research output: Contribution to journal › Letter › peer-review

Abstract

Classical general relativity allows time travel, but Hawking (1992 Phys. Rev. D 46 603) conjectured that quantum mechanics ultimately prevents it. Here we propose a feasible experiment to test Hawking’s chronology protection conjecture in optics. In this scheme, time travel is inherently related to lasing, and the amplified vacuum fluctuations above laser threshold establish the quantum limits of time travel.

Original language	English
Article number	14LT01
Journal	Classical and Quantum Gravity
Volume	43
Issue number	14
DOIs	https://doi.org/10.1088/1361-6382/ae88aa
State	Published - 28 Jul 2026

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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10.1088/1361-6382/ae88aaLicense: CC BY

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abstract = "Classical general relativity allows time travel, but Hawking (1992 Phys. Rev. D 46 603) conjectured that quantum mechanics ultimately prevents it. Here we propose a feasible experiment to test Hawking{\textquoteright}s chronology protection conjecture in optics. In this scheme, time travel is inherently related to lasing, and the amplified vacuum fluctuations above laser threshold establish the quantum limits of time travel.",

author = "David Bermudez and Ulf Leonhardt",

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AU - Leonhardt, Ulf

N1 - Publisher Copyright: © 2026 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

PY - 2026/7/28

Y1 - 2026/7/28

N2 - Classical general relativity allows time travel, but Hawking (1992 Phys. Rev. D 46 603) conjectured that quantum mechanics ultimately prevents it. Here we propose a feasible experiment to test Hawking’s chronology protection conjecture in optics. In this scheme, time travel is inherently related to lasing, and the amplified vacuum fluctuations above laser threshold establish the quantum limits of time travel.

AB - Classical general relativity allows time travel, but Hawking (1992 Phys. Rev. D 46 603) conjectured that quantum mechanics ultimately prevents it. Here we propose a feasible experiment to test Hawking’s chronology protection conjecture in optics. In this scheme, time travel is inherently related to lasing, and the amplified vacuum fluctuations above laser threshold establish the quantum limits of time travel.

UR - https://www.scopus.com/pages/publications/105045738100

U2 - 10.1088/1361-6382/ae88aa

DO - 10.1088/1361-6382/ae88aa

M3 - Letter

SN - 0264-9381

VL - 43

JO - Classical and Quantum Gravity

JF - Classical and Quantum Gravity

IS - 14

M1 - 14LT01

ER -

Optical time travel: proposal for testing Hawking’s chronology protection conjecture in an optical analogue

Abstract

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