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1. Verfasser: Mannheim, Philip D.
Format: Preprint
Veröffentlicht: 2025
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Online-Zugang:https://arxiv.org/abs/2504.12068
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author Mannheim, Philip D.
author_facet Mannheim, Philip D.
contents When excited states decay the time evolution operator $U(t)=e^{-iHt}$ does not obey $U^{\dagger}(t)U(t)=I$. Nonetheless, probability conservation is not lost if one includes both excitation and decay, though it takes a different form. Specifically, if the eigenspectrum of a Hamiltonian is complete, then due to $CPT$ symmetry, a symmetry that holds for all physical systems, there must exist an operator $V$ that effects $VHV^{-1}=H^{\dagger}$, so that $V^{-1}U^{\dagger}(t)VU(t)=I$. In consequence, the time delay associated with decay must be accompanied by an equal and opposite time advance for excitation. Thus when a photon excites an atom the spontaneous emission of a photon from the excited state must occur without any decay time delay at all. An effect of this form together with an associated negative time delay appear to have recently been reported by Sinclair et. al., PRX Quantum \textbf{3}, 010314 (2022) and Angulo et. al., arXiv:2409.03680 [quant-ph].
format Preprint
id arxiv_https___arxiv_org_abs_2504_12068
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Time Advance and Probability Conservation in PT-Symmetric Quantum Mechanics
Mannheim, Philip D.
Quantum Physics
High Energy Physics - Theory
When excited states decay the time evolution operator $U(t)=e^{-iHt}$ does not obey $U^{\dagger}(t)U(t)=I$. Nonetheless, probability conservation is not lost if one includes both excitation and decay, though it takes a different form. Specifically, if the eigenspectrum of a Hamiltonian is complete, then due to $CPT$ symmetry, a symmetry that holds for all physical systems, there must exist an operator $V$ that effects $VHV^{-1}=H^{\dagger}$, so that $V^{-1}U^{\dagger}(t)VU(t)=I$. In consequence, the time delay associated with decay must be accompanied by an equal and opposite time advance for excitation. Thus when a photon excites an atom the spontaneous emission of a photon from the excited state must occur without any decay time delay at all. An effect of this form together with an associated negative time delay appear to have recently been reported by Sinclair et. al., PRX Quantum \textbf{3}, 010314 (2022) and Angulo et. al., arXiv:2409.03680 [quant-ph].
title Time Advance and Probability Conservation in PT-Symmetric Quantum Mechanics
topic Quantum Physics
High Energy Physics - Theory
url https://arxiv.org/abs/2504.12068