Characteristic time operators as quantum clocks

Fuente: arXiv
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Main Authors: Farrales, Ralph Adrian E., Galapon, Eric A.
Format: Preprint
Published: 2024
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author Farrales, Ralph Adrian E.
Galapon, Eric A.
author_facet Farrales, Ralph Adrian E.
Galapon, Eric A.
contents We consider the characteristic time operator $\mathsf{T}$ introduced in [E. A. Galapon, Proc. R. Soc. Lond. A, 458:2671 (2002)] which is bounded and self-adjoint. For a semibounded discrete Hamiltonian $\mathsf{H}$ with some growth condition, $\mathsf{T}$ satisfies the canonical relation $[\mathsf{T},\mathsf{H}]|ψ\rangle=i\hbar|ψ\rangle$ for $|ψ\rangle$ in a dense subspace of the Hilbert space. While $\mathsf{T}$ is not covariant, we show that it still satisfies the canonical relation in a set of times of total measure zero called the time invariant set $\mathscr{T}$. In the neighborhood of each time $t$ in $\mathscr{T}$, $\mathsf{T}$ is still canonically conjugate to $\mathsf{H}$ and its expectation value gives the parametric time. Its two-dimensional projection saturates the time-energy uncertainty relation in the neighborhood of $\mathscr{T}$, and is proportional to the Pauli matrix $σ_y$. Thus, one can construct a quantum clock that tells the time in the neighborhood of $\mathscr{T}$ by measuring a compatible observable.
format Preprint
id arxiv_https___arxiv_org_abs_2409_03364
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Characteristic time operators as quantum clocks
Farrales, Ralph Adrian E.
Galapon, Eric A.
Quantum Physics
We consider the characteristic time operator $\mathsf{T}$ introduced in [E. A. Galapon, Proc. R. Soc. Lond. A, 458:2671 (2002)] which is bounded and self-adjoint. For a semibounded discrete Hamiltonian $\mathsf{H}$ with some growth condition, $\mathsf{T}$ satisfies the canonical relation $[\mathsf{T},\mathsf{H}]|ψ\rangle=i\hbar|ψ\rangle$ for $|ψ\rangle$ in a dense subspace of the Hilbert space. While $\mathsf{T}$ is not covariant, we show that it still satisfies the canonical relation in a set of times of total measure zero called the time invariant set $\mathscr{T}$. In the neighborhood of each time $t$ in $\mathscr{T}$, $\mathsf{T}$ is still canonically conjugate to $\mathsf{H}$ and its expectation value gives the parametric time. Its two-dimensional projection saturates the time-energy uncertainty relation in the neighborhood of $\mathscr{T}$, and is proportional to the Pauli matrix $σ_y$. Thus, one can construct a quantum clock that tells the time in the neighborhood of $\mathscr{T}$ by measuring a compatible observable.
title Characteristic time operators as quantum clocks
topic Quantum Physics
url https://arxiv.org/abs/2409.03364