---
_id: '15269'
abstract:
- lang: eng
  text: We study different aspects of quantum field theory at finite density using
    methods from quantum information theory. For simplicity we focus on massive Dirac
    fermions with nonzero chemical potential, and work in 1 + 1 space-time dimensions.
    Using the entanglement entropy on an interval, we construct an entropic <jats:italic>c</jats:italic>-function
    that is finite. Unlike what happens in Lorentz-invariant theories, this <jats:italic>c</jats:italic>-function
    exhibits a strong violation of monotonicity; it also encodes the creation of long-range
    entanglement from the Fermi surface. Motivated by previous works on lattice models,
    we next calculate numerically the Renyi entropies and find Friedel-type oscillations;
    these are understood in terms of a defect operator product expansion. Furthermore,
    we consider the mutual information as a measure of correlation functions between
    different regions. Using a long-distance expansion previously developed by Cardy,
    we argue that the mutual information detects Fermi surface correlations already
    at leading order in the expansion. We also analyze the relative entropy and its
    Renyi generalizations in order to distinguish states with different charge and/or
    mass. In particular, we show that states in different superselection sectors give
    rise to a super-extensive behavior in the relative entropy. Finally, we discuss
    possible extensions to interacting theories, and argue for the relevance of some
    of these measures for probing non-Fermi liquids.
acknowledgement: "We thank H. Casini for many interesting discussions and comments
  on the manuscript.\r\nLD is supported by CNEA and UNCuyo, Inst. Balseiro. RM is
  supported by IST Austria.\r\nMS is supported by CONICET and UNCuyo, Inst. Balseiro.
  GT is supported by CONICET\r\n(PIP grant 11220150100299), ANPCyT (PICT 2018-2517),
  CNEA, and UNCuyo,\r\nInst. Balseiro."
article_number: '79'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Lucas
  full_name: Daguerre, Lucas
  last_name: Daguerre
- first_name: Raimel A
  full_name: Medina Ramos, Raimel A
  id: CE680B90-D85A-11E9-B684-C920E6697425
  last_name: Medina Ramos
  orcid: 0000-0002-5383-2869
- first_name: Mario
  full_name: Solís, Mario
  last_name: Solís
- first_name: Gonzalo
  full_name: Torroba, Gonzalo
  last_name: Torroba
citation:
  ama: Daguerre L, Medina Ramos RA, Solís M, Torroba G. Aspects of quantum information
    in finite density field theory. <i>Journal of High Energy Physics</i>. 2021;2021(3).
    doi:<a href="https://doi.org/10.1007/jhep03(2021)079">10.1007/jhep03(2021)079</a>
  apa: Daguerre, L., Medina Ramos, R. A., Solís, M., &#38; Torroba, G. (2021). Aspects
    of quantum information in finite density field theory. <i>Journal of High Energy
    Physics</i>. Springer Nature. <a href="https://doi.org/10.1007/jhep03(2021)079">https://doi.org/10.1007/jhep03(2021)079</a>
  chicago: Daguerre, Lucas, Raimel A Medina Ramos, Mario Solís, and Gonzalo Torroba.
    “Aspects of Quantum Information in Finite Density Field Theory.” <i>Journal of
    High Energy Physics</i>. Springer Nature, 2021. <a href="https://doi.org/10.1007/jhep03(2021)079">https://doi.org/10.1007/jhep03(2021)079</a>.
  ieee: L. Daguerre, R. A. Medina Ramos, M. Solís, and G. Torroba, “Aspects of quantum
    information in finite density field theory,” <i>Journal of High Energy Physics</i>,
    vol. 2021, no. 3. Springer Nature, 2021.
  ista: Daguerre L, Medina Ramos RA, Solís M, Torroba G. 2021. Aspects of quantum
    information in finite density field theory. Journal of High Energy Physics. 2021(3),
    79.
  mla: Daguerre, Lucas, et al. “Aspects of Quantum Information in Finite Density Field
    Theory.” <i>Journal of High Energy Physics</i>, vol. 2021, no. 3, 79, Springer
    Nature, 2021, doi:<a href="https://doi.org/10.1007/jhep03(2021)079">10.1007/jhep03(2021)079</a>.
  short: L. Daguerre, R.A. Medina Ramos, M. Solís, G. Torroba, Journal of High Energy
    Physics 2021 (2021).
corr_author: '1'
date_created: 2024-04-03T07:51:06Z
date_published: 2021-03-08T00:00:00Z
date_updated: 2025-09-10T10:15:02Z
day: '08'
ddc:
- '530'
department:
- _id: MaSe
doi: 10.1007/jhep03(2021)079
external_id:
  arxiv:
  - '2011.01252'
  isi:
  - '000627376600004'
file:
- access_level: open_access
  checksum: 4f540e63988ee87173e02f51a19a6672
  content_type: application/pdf
  creator: dernst
  date_created: 2024-04-10T09:18:38Z
  date_updated: 2024-04-10T09:18:38Z
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  file_size: 5389195
  relation: main_file
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file_date_updated: 2024-04-10T09:18:38Z
has_accepted_license: '1'
intvolume: '      2021'
isi: 1
issue: '3'
keyword:
- Nuclear and High Energy Physics
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '03'
oa: 1
oa_version: Published Version
publication: Journal of High Energy Physics
publication_identifier:
  issn:
  - 1029-8479
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Aspects of quantum information in finite density field theory
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 2021
year: '2021'
...