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Entanglement evolution after a global quench across a conformal defect
by Luca Capizzi, Viktor Eisler
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Submission summary
| Authors (as registered SciPost users): | Luca Capizzi · Viktor Eisler |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2209.03297v4 (pdf) |
| Date accepted: | 2023-01-10 |
| Date submitted: | 2022-12-01 13:30 |
| Submitted by: | Capizzi, Luca |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
We study the evolution of entanglement after a global quench in a one-dimensional quantum system with a localized impurity. For systems described by a conformal field theory, the entanglement entropy between the two regions separated by the defect grows linearly in time. Introducing the notion of boundary twist fields, we show how the slope of this growth can be related to the effective central charge that emerges in the study of ground-state entropy in the presence of the defect. On the other hand, we also consider a particular lattice realization of the quench in a free-fermion chain with a conformal defect. Starting from a gapped initial state, we obtain the slope via a quasiparticle ansatz and observe small discrepancies between the field theory and lattice results, which persist even in the limit of a vanishing gap.
List of changes
Added a sentence in the Discussion:
- ’In fact, in the latter case the entropy growth is logarithmic,
and the prefactor is exactly given by cef f even on the lattice [28]. This is due to the fact, that in this
low-energy quench protocol the precise form of the dispersion does not play a role'
-Slight modification of the sentence after Eq. 57:
'The subleading term for μ = 1 is likely to be logarithmic in time, with some superim-
posed oscillations, whereas it seems to be given by a constant for μ = 0.1. However, a closer
inspection of the latter case indicates that the corrections are probably still logarithmic,
albeit with a tiny prefactor, which is also supported by calculations for L = 200.'
Published as SciPost Phys. 14, 070 (2023)