# Notes on time entanglement and pseudo-entropy

Source: [Notes on time entanglement and pseudo-entropy](<https://www.sota2.com/research/paper/68fa46df1e209131ce9239e8>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-25T06:01:09.691Z

Authors: K. Narayan, Hitesh K. Saini

Published: 2023-03-02T14:33:20.000Z

## Abstract

Following arXiv:2210.12963 \[hep-th\], we investigate aspects of the time evolution operator regarded as a density operator and associated entanglement-like structures in various quantum systems. These involve timelike separations and generically lead to complex-valued entropy, although there are interesting real subfamilies. There are many parallels and close relations with reduced transition matrices and pseudo-entropy, which we discuss and clarify. For instance, a related quantity involves the time evolution operator along with a projection onto some initial state, which amounts to analysing pseudo-entropy for the initial state and its time-evolved final state.

## Recorded benchmark results

A research result applies to its stated dataset, split, metric and evaluation configuration. Compare like-for-like settings, preserve the metric's unit and direction, and distinguish paper-reported results from independent reproduction. The best result recorded here is not a claim of exhaustive, current global coverage.

## Original sources and implementation

[Original paper](<https://arxiv.org/abs/2303.01307>)

[PDF](<https://arxiv.org/pdf/2303.01307.pdf>)