---
_id: '14334'
abstract:
- lang: eng
  text: Quantum kinetically constrained models have recently attracted significant
    attention due to their anomalous dynamics and thermalization. In this work, we
    introduce a hitherto unexplored family of kinetically constrained models featuring
    conserved particle number and strong inversion-symmetry breaking due to facilitated
    hopping. We demonstrate that these models provide a generic example of so-called
    quantum Hilbert space fragmentation, that is manifested in disconnected sectors
    in the Hilbert space that are not apparent in the computational basis. Quantum
    Hilbert space fragmentation leads to an exponential in system size number of eigenstates
    with exactly zero entanglement entropy across several bipartite cuts. These eigenstates
    can be probed dynamically using quenches from simple initial product states. In
    addition, we study the particle spreading under unitary dynamics launched from
    the domain wall state, and find faster than diffusive dynamics at high particle
    densities, that crosses over into logarithmically slow relaxation at smaller densities.
    Using a classically simulable cellular automaton, we reproduce the logarithmic
    dynamics observed in the quantum case. Our work suggests that particle conserving
    constrained models with inversion symmetry breaking realize so far unexplored
    dynamical behavior and invite their further theoretical and experimental studies.
acknowledgement: "We would like to thank Raimel A. Medina, Hansveer Singh, and Dmitry
  Abanin for useful\r\ndiscussions.The authors acknowledge support by the European
  Research Council\r\n(ERC) under the European Union’s Horizon 2020 research and innovation
  program (Grant\r\nAgreement No. 850899). We acknowledge support by the Erwin Schrödinger
  International\r\nInstitute for Mathematics and Physics (ESI)."
article_number: '093'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
- first_name: Marko
  full_name: Ljubotina, Marko
  id: F75EE9BE-5C90-11EA-905D-16643DDC885E
  last_name: Ljubotina
  orcid: 0000-0003-0038-7068
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Brighi P, Ljubotina M, Serbyn M. Hilbert space fragmentation and slow dynamics
    in particle-conserving quantum East models. <i>SciPost Physics</i>. 2023;15(3).
    doi:<a href="https://doi.org/10.21468/scipostphys.15.3.093">10.21468/scipostphys.15.3.093</a>
  apa: Brighi, P., Ljubotina, M., &#38; Serbyn, M. (2023). Hilbert space fragmentation
    and slow dynamics in particle-conserving quantum East models. <i>SciPost Physics</i>.
    SciPost Foundation. <a href="https://doi.org/10.21468/scipostphys.15.3.093">https://doi.org/10.21468/scipostphys.15.3.093</a>
  chicago: Brighi, Pietro, Marko Ljubotina, and Maksym Serbyn. “Hilbert Space Fragmentation
    and Slow Dynamics in Particle-Conserving Quantum East Models.” <i>SciPost Physics</i>.
    SciPost Foundation, 2023. <a href="https://doi.org/10.21468/scipostphys.15.3.093">https://doi.org/10.21468/scipostphys.15.3.093</a>.
  ieee: P. Brighi, M. Ljubotina, and M. Serbyn, “Hilbert space fragmentation and slow
    dynamics in particle-conserving quantum East models,” <i>SciPost Physics</i>,
    vol. 15, no. 3. SciPost Foundation, 2023.
  ista: Brighi P, Ljubotina M, Serbyn M. 2023. Hilbert space fragmentation and slow
    dynamics in particle-conserving quantum East models. SciPost Physics. 15(3), 093.
  mla: Brighi, Pietro, et al. “Hilbert Space Fragmentation and Slow Dynamics in Particle-Conserving
    Quantum East Models.” <i>SciPost Physics</i>, vol. 15, no. 3, 093, SciPost Foundation,
    2023, doi:<a href="https://doi.org/10.21468/scipostphys.15.3.093">10.21468/scipostphys.15.3.093</a>.
  short: P. Brighi, M. Ljubotina, M. Serbyn, SciPost Physics 15 (2023).
date_created: 2023-09-14T13:08:23Z
date_published: 2023-09-13T00:00:00Z
date_updated: 2023-09-20T10:46:29Z
day: '13'
ddc:
- '530'
department:
- _id: MaSe
doi: 10.21468/scipostphys.15.3.093
ec_funded: 1
external_id:
  arxiv:
  - '2210.15607'
file:
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intvolume: '        15'
issue: '3'
keyword:
- General Physics and Astronomy
language:
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license: https://creativecommons.org/licenses/by/4.0/
month: '09'
oa: 1
oa_version: Published Version
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '850899'
  name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication: SciPost Physics
publication_identifier:
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publication_status: published
publisher: SciPost Foundation
quality_controlled: '1'
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status: public
title: Hilbert space fragmentation and slow dynamics in particle-conserving quantum
  East models
tmp:
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  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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 15
year: '2023'
...
---
_id: '13963'
abstract:
- lang: eng
  text: The many-body localization (MBL) proximity effect is an intriguing phenomenon
    where a thermal bath localizes due to the interaction with a disordered system.
    The interplay of thermal and nonergodic behavior in these systems gives rise to
    a rich phase diagram, whose exploration is an active field of research. In this
    paper, we study a bosonic Hubbard model featuring two particle species representing
    the bath and the disordered system. Using state-of-the-art numerical techniques,
    we investigate the dynamics of the model in different regimes, based on which
    we obtain a tentative phase diagram as a function of coupling strength and bath
    size. When the bath is composed of a single particle, we observe clear signatures
    of a transition from an MBL proximity effect to a delocalized phase. Increasing
    the bath size, however, its thermalizing effect becomes stronger and eventually
    the whole system delocalizes in the range of moderate interaction strengths studied.
    In this regime, we characterize particle transport, revealing diffusive behavior
    of the originally localized bosons.
acknowledgement: "We thank A. A. Michailidis and A. Mirlin for insightful discussions.
  P.B., M.L., and M.S. acknowledge support by the European Research Council (ERC)
  under the European Union’s Horizon 2020 research and innovation program (Grant Agreement
  No. 850899). D.A. was\r\nsupported by the European Research Council (ERC) under
  the European Union’s Horizon 2020 research and innovation program (Grant Agreement
  No. 864597) and by the Swiss National Science Foundation. P.B., M.L., and M.S. acknowledge
  PRACE for awarding us access to Joliot-Curie at GENCI@CEA, France, where the TEBD
  simulations were performed. The TEBD simulations were performed using the ITensor
  library [60]."
article_number: '054201'
article_processing_charge: Yes (in subscription journal)
article_type: original
arxiv: 1
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
- first_name: Marko
  full_name: Ljubotina, Marko
  id: F75EE9BE-5C90-11EA-905D-16643DDC885E
  last_name: Ljubotina
- first_name: Dmitry A.
  full_name: Abanin, Dmitry A.
  last_name: Abanin
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Brighi P, Ljubotina M, Abanin DA, Serbyn M. Many-body localization proximity
    effect in a two-species bosonic Hubbard model. <i>Physical Review B</i>. 2023;108(5).
    doi:<a href="https://doi.org/10.1103/physrevb.108.054201">10.1103/physrevb.108.054201</a>
  apa: Brighi, P., Ljubotina, M., Abanin, D. A., &#38; Serbyn, M. (2023). Many-body
    localization proximity effect in a two-species bosonic Hubbard model. <i>Physical
    Review B</i>. American Physical Society. <a href="https://doi.org/10.1103/physrevb.108.054201">https://doi.org/10.1103/physrevb.108.054201</a>
  chicago: Brighi, Pietro, Marko Ljubotina, Dmitry A. Abanin, and Maksym Serbyn. “Many-Body
    Localization Proximity Effect in a Two-Species Bosonic Hubbard Model.” <i>Physical
    Review B</i>. American Physical Society, 2023. <a href="https://doi.org/10.1103/physrevb.108.054201">https://doi.org/10.1103/physrevb.108.054201</a>.
  ieee: P. Brighi, M. Ljubotina, D. A. Abanin, and M. Serbyn, “Many-body localization
    proximity effect in a two-species bosonic Hubbard model,” <i>Physical Review B</i>,
    vol. 108, no. 5. American Physical Society, 2023.
  ista: Brighi P, Ljubotina M, Abanin DA, Serbyn M. 2023. Many-body localization proximity
    effect in a two-species bosonic Hubbard model. Physical Review B. 108(5), 054201.
  mla: Brighi, Pietro, et al. “Many-Body Localization Proximity Effect in a Two-Species
    Bosonic Hubbard Model.” <i>Physical Review B</i>, vol. 108, no. 5, 054201, American
    Physical Society, 2023, doi:<a href="https://doi.org/10.1103/physrevb.108.054201">10.1103/physrevb.108.054201</a>.
  short: P. Brighi, M. Ljubotina, D.A. Abanin, M. Serbyn, Physical Review B 108 (2023).
date_created: 2023-08-05T18:25:22Z
date_published: 2023-08-01T00:00:00Z
date_updated: 2023-08-07T09:51:39Z
day: '01'
ddc:
- '530'
department:
- _id: MaSe
doi: 10.1103/physrevb.108.054201
ec_funded: 1
external_id:
  arxiv:
  - '2303.16876'
file:
- access_level: open_access
  checksum: f763000339b5fd543c14377109920690
  content_type: application/pdf
  creator: dernst
  date_created: 2023-08-07T09:48:08Z
  date_updated: 2023-08-07T09:48:08Z
  file_id: '13981'
  file_name: 2023_PhysRevB_Brighi.pdf
  file_size: 3051398
  relation: main_file
  success: 1
file_date_updated: 2023-08-07T09:48:08Z
has_accepted_license: '1'
intvolume: '       108'
issue: '5'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '850899'
  name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication: Physical Review B
publication_identifier:
  eissn:
  - 2469-9969
  issn:
  - 2469-9950
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Many-body localization proximity effect in a two-species bosonic Hubbard model
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: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 108
year: '2023'
...
---
_id: '12732'
abstract:
- lang: eng
  text: "Nonergodic systems, whose out-of-equilibrium dynamics fail to thermalize,
    provide a fascinating research direction both for fundamental reasons and for
    application in state of the art quantum devices.\r\nGoing beyond the description
    of statistical mechanics, ergodicity breaking yields a new paradigm in quantum
    many-body physics, introducing novel phases of matter with no counterpart at equilibrium.\r\nIn
    this Thesis, we address different open questions in the field, focusing on disorder-induced
    many-body localization (MBL) and on weak ergodicity breaking in kinetically constrained
    models.\r\nIn particular, we contribute to the debate about transport in kinetically
    constrained models, studying the effect of $U(1)$ conservation and inversion-symmetry
    breaking in a family of quantum East models.\r\nUsing tensor network techniques,
    we analyze the dynamics of large MBL systems beyond the limit of exact numerical
    methods.\r\nIn this setting, we approach the debated topic of the coexistence
    of localized and thermal eigenstates separated by energy thresholds known as many-body
    mobility edges.\r\nInspired by recent experiments, our work further investigates
    the localization of a small bath induced by the coupling to a large localized
    chain, the so-called MBL proximity effect.\r\n\r\nIn the first Chapter, we introduce
    a family of particle-conserving kinetically constrained models, inspired by the
    quantum East model.\r\nThe system we study features strong inversion-symmetry
    breaking, due to the nature of the correlated hopping.\r\nWe show that these models
    host so-called quantum Hilbert space fragmentation, consisting of disconnected
    subsectors in an entangled basis, and further provide an analytical description
    of this phenomenon.\r\nWe further probe its effect on dynamics of simple product
    states, showing revivals in fidelity and local observalbes.\r\nThe study of dynamics
    within the largest subsector reveals an anomalous transient superdiffusive behavior
    crossing over to slow logarithmic dynamics at later times.\r\nThis work suggests
    that particle conserving constrained models with inversion-symmetry breaking realize
    new universality classes of dynamics and invite their further theoretical and
    experimental studies.\r\n\r\nNext, we use kinetic constraints and disorder to
    design a model with many-body mobility edges in particle density.\r\nThis feature
    allows to study the dynamics of localized and thermal states in large systems
    beyond the limitations of previous studies.\r\nThe time-evolution shows typical
    signatures of localization at small densities, replaced by thermal behavior at
    larger densities.\r\nOur results provide evidence in favor of the stability of
    many-body mobility edges, which was recently challenged by a theoretical argument.\r\nTo
    support our findings, we probe the mechanism proposed as a cause of delocalization
    in many-body localized systems with mobility edges suggesting its ineffectiveness
    in the model studied.\r\n\r\nIn the last Chapter of this Thesis, we address the
    topic of many-body localization proximity effect.\r\nWe study a model inspired
    by recent experiments, featuring Anderson localized coupled to a small bath of
    free hard-core bosons.\r\nThe interaction among the two particle species results
    in non-trivial dynamics, which we probe using tensor network techniques.\r\nOur
    simulations show convincing evidence of many-body localization proximity effect
    when the bath is composed by a single free particle and interactions are strong.\r\nWe
    furthter observe an anomalous entanglement dynamics, which we explain through
    a phenomenological theory.\r\nFinally, we extract highly excited eigenstates of
    large systems, providing supplementary evidence in favor of our findings."
acknowledged_ssus:
- _id: ScienComp
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
citation:
  ama: Brighi P. Ergodicity breaking in disordered and kinetically constrained quantum
    many-body systems. 2023. doi:<a href="https://doi.org/10.15479/at:ista:12732">10.15479/at:ista:12732</a>
  apa: Brighi, P. (2023). <i>Ergodicity breaking in disordered and kinetically constrained
    quantum many-body systems</i>. Institute of Science and Technology Austria. <a
    href="https://doi.org/10.15479/at:ista:12732">https://doi.org/10.15479/at:ista:12732</a>
  chicago: Brighi, Pietro. “Ergodicity Breaking in Disordered and Kinetically Constrained
    Quantum Many-Body Systems.” Institute of Science and Technology Austria, 2023.
    <a href="https://doi.org/10.15479/at:ista:12732">https://doi.org/10.15479/at:ista:12732</a>.
  ieee: P. Brighi, “Ergodicity breaking in disordered and kinetically constrained
    quantum many-body systems,” Institute of Science and Technology Austria, 2023.
  ista: Brighi P. 2023. Ergodicity breaking in disordered and kinetically constrained
    quantum many-body systems. Institute of Science and Technology Austria.
  mla: Brighi, Pietro. <i>Ergodicity Breaking in Disordered and Kinetically Constrained
    Quantum Many-Body Systems</i>. Institute of Science and Technology Austria, 2023,
    doi:<a href="https://doi.org/10.15479/at:ista:12732">10.15479/at:ista:12732</a>.
  short: P. Brighi, Ergodicity Breaking in Disordered and Kinetically Constrained
    Quantum Many-Body Systems, Institute of Science and Technology Austria, 2023.
date_created: 2023-03-17T13:30:48Z
date_published: 2023-03-21T00:00:00Z
date_updated: 2023-09-20T10:44:12Z
day: '21'
ddc:
- '530'
degree_awarded: PhD
department:
- _id: GradSch
- _id: MaSe
doi: 10.15479/at:ista:12732
ec_funded: 1
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license: https://creativecommons.org/licenses/by-nc-sa/4.0/
month: '03'
oa: 1
oa_version: None
page: '158'
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '850899'
  name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
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  - id: '11470'
    relation: part_of_dissertation
    status: public
  - id: '8308'
    relation: part_of_dissertation
    status: public
  - id: '11469'
    relation: part_of_dissertation
    status: public
  - id: '12750'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
title: Ergodicity breaking in disordered and kinetically constrained quantum many-body
  systems
tmp:
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    BY-NC-SA 4.0)
  short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '11469'
abstract:
- lang: eng
  text: Thermalizing and localized many-body quantum systems present two distinct
    dynamical phases of matter. Recently the fate of a localized system coupled to
    a thermalizing system viewed as a quantum bath received significant theoretical
    and experimental attention. In this work, we study a mobile impurity, representing
    a small quantum bath, that interacts locally with an Anderson insulator with a
    finite density of localized particles. Using static Hartree approximation to obtain
    an effective disorder strength, we formulate an analytic criterion for the perturbative
    stability of the localization. Next, we use an approximate dynamical Hartree method
    and the quasi-exact time-evolved block decimation (TEBD) algorithm to study the
    dynamics of the system. We find that the dynamical Hartree approach which completely
    ignores entanglement between the impurity and localized particles predicts the
    delocalization of the system. In contrast, the full numerical simulation of the
    unitary dynamics with TEBD suggests the stability of localization on numerically
    accessible timescales. Finally, using an extension of the density matrix renormalization
    group algorithm to excited states (DMRG-X), we approximate the highly excited
    eigenstates of the system. We find that the impurity remains localized in the
    eigenstates and entanglement is enhanced in a finite region around the position
    of the impurity, confirming the dynamical predictions. Dynamics and the DMRG-X
    results provide compelling evidence for the stability of localization.
acknowledged_ssus:
- _id: ScienComp
acknowledgement: We thank M. Ljubotina for insightful discussions. P. B., A. M. and
  M. S. acknowledge support by the European Research Council (ERC) under the European
  Union’s Horizon 2020 research and innovation program (Grant Agreement No. 850899).
  D. A. was supported by the Swiss National Science Foundation and by the European
  Research Council (ERC) under the European Union’s Horizon 2020 research and innovation
  program (Grant Agreement No. 864597). The development of parallel TEBD code was
  supported by S. Elefante from the Scientific Computing (SciComp) that is part of
  Scientific Service Units (SSU) of IST Austria. Some of the computations were performed
  on the Baobab cluster of the University of Geneva.
article_number: '224208'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
- first_name: Alexios
  full_name: Michailidis, Alexios
  id: 36EBAD38-F248-11E8-B48F-1D18A9856A87
  last_name: Michailidis
  orcid: 0000-0002-8443-1064
- first_name: Kristina
  full_name: Kirova, Kristina
  id: 4aeda2ae-f847-11ec-98e0-c4a66fe174d4
  last_name: Kirova
- first_name: Dmitry A.
  full_name: Abanin, Dmitry A.
  last_name: Abanin
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Brighi P, Michailidis A, Kirova K, Abanin DA, Serbyn M. Localization of a mobile
    impurity interacting with an Anderson insulator. <i>Physical Review B</i>. 2022;105(22).
    doi:<a href="https://doi.org/10.1103/physrevb.105.224208">10.1103/physrevb.105.224208</a>
  apa: Brighi, P., Michailidis, A., Kirova, K., Abanin, D. A., &#38; Serbyn, M. (2022).
    Localization of a mobile impurity interacting with an Anderson insulator. <i>Physical
    Review B</i>. American Physical Society. <a href="https://doi.org/10.1103/physrevb.105.224208">https://doi.org/10.1103/physrevb.105.224208</a>
  chicago: Brighi, Pietro, Alexios Michailidis, Kristina Kirova, Dmitry A. Abanin,
    and Maksym Serbyn. “Localization of a Mobile Impurity Interacting with an Anderson
    Insulator.” <i>Physical Review B</i>. American Physical Society, 2022. <a href="https://doi.org/10.1103/physrevb.105.224208">https://doi.org/10.1103/physrevb.105.224208</a>.
  ieee: P. Brighi, A. Michailidis, K. Kirova, D. A. Abanin, and M. Serbyn, “Localization
    of a mobile impurity interacting with an Anderson insulator,” <i>Physical Review
    B</i>, vol. 105, no. 22. American Physical Society, 2022.
  ista: Brighi P, Michailidis A, Kirova K, Abanin DA, Serbyn M. 2022. Localization
    of a mobile impurity interacting with an Anderson insulator. Physical Review B.
    105(22), 224208.
  mla: Brighi, Pietro, et al. “Localization of a Mobile Impurity Interacting with
    an Anderson Insulator.” <i>Physical Review B</i>, vol. 105, no. 22, 224208, American
    Physical Society, 2022, doi:<a href="https://doi.org/10.1103/physrevb.105.224208">10.1103/physrevb.105.224208</a>.
  short: P. Brighi, A. Michailidis, K. Kirova, D.A. Abanin, M. Serbyn, Physical Review
    B 105 (2022).
date_created: 2022-06-29T20:19:51Z
date_published: 2022-06-27T00:00:00Z
date_updated: 2023-09-05T12:12:52Z
day: '27'
department:
- _id: MaSe
doi: 10.1103/physrevb.105.224208
ec_funded: 1
external_id:
  arxiv:
  - '2111.08603'
  isi:
  - '000823050000001'
intvolume: '       105'
isi: 1
issue: '22'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: ' https://doi.org/10.48550/arXiv.2111.08603 Focus to learn more'
month: '06'
oa: 1
oa_version: Preprint
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '850899'
  name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication: Physical Review B
publication_identifier:
  eissn:
  - 2469-9969
  issn:
  - 2469-9950
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
  record:
  - id: '12732'
    relation: dissertation_contains
    status: public
status: public
title: Localization of a mobile impurity interacting with an Anderson insulator
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 105
year: '2022'
...
---
_id: '11470'
abstract:
- lang: eng
  text: Many-body localization (MBL) is an example of a dynamical phase of matter
    that avoids thermalization. While the MBL phase is robust to weak local perturbations,
    the fate of an MBL system coupled to a thermalizing quantum system that represents
    a “heat bath” is an open question that is actively investigated theoretically
    and experimentally. In this work, we consider the stability of an Anderson insulator
    with a finite density of particles interacting with a single mobile impurity—a
    small quantum bath. We give perturbative arguments that support the stability
    of localization in the strong interaction regime. Large-scale tensor network simulations
    of dynamics are employed to corroborate the presence of the localized phase and
    give quantitative predictions in the thermodynamic limit. We develop a phenomenological
    description of the dynamics in the strong interaction regime, and we demonstrate
    that the impurity effectively turns the Anderson insulator into an MBL phase,
    giving rise to nontrivial entanglement dynamics well captured by our phenomenology.
acknowledged_ssus:
- _id: ScienComp
acknowledgement: We acknowledge useful discussions with M. Ljubotina. P. B., A. M.,
  and M. S. were supported by the European Research Council (ERC) under the European
  Union’s Horizon 2020 research and innovation program (Grant Agreement No. 850899).
  D.A. was supported by the Swiss National Science Foundation and by the European
  Research Council (ERC) under the European Union’s Horizon 2020 research and innovation
  program (Grant Agreement No. 864597). The development of parallel TEBD code was
  was supported by S. Elefante from the Scientific Computing (SciComp) that is part
  of Scientific Service Units (SSU) of IST Austria. Some of the computations were
  performed on the Baobab cluster of the University of Geneva.
article_number: L220203
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
- first_name: Alexios A.
  full_name: Michailidis, Alexios A.
  last_name: Michailidis
- first_name: Dmitry A.
  full_name: Abanin, Dmitry A.
  last_name: Abanin
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Brighi P, Michailidis AA, Abanin DA, Serbyn M. Propagation of many-body localization
    in an Anderson insulator. <i>Physical Review B</i>. 2022;105(22). doi:<a href="https://doi.org/10.1103/physrevb.105.l220203">10.1103/physrevb.105.l220203</a>
  apa: Brighi, P., Michailidis, A. A., Abanin, D. A., &#38; Serbyn, M. (2022). Propagation
    of many-body localization in an Anderson insulator. <i>Physical Review B</i>.
    American Physical Society. <a href="https://doi.org/10.1103/physrevb.105.l220203">https://doi.org/10.1103/physrevb.105.l220203</a>
  chicago: Brighi, Pietro, Alexios A. Michailidis, Dmitry A. Abanin, and Maksym Serbyn.
    “Propagation of Many-Body Localization in an Anderson Insulator.” <i>Physical
    Review B</i>. American Physical Society, 2022. <a href="https://doi.org/10.1103/physrevb.105.l220203">https://doi.org/10.1103/physrevb.105.l220203</a>.
  ieee: P. Brighi, A. A. Michailidis, D. A. Abanin, and M. Serbyn, “Propagation of
    many-body localization in an Anderson insulator,” <i>Physical Review B</i>, vol.
    105, no. 22. American Physical Society, 2022.
  ista: Brighi P, Michailidis AA, Abanin DA, Serbyn M. 2022. Propagation of many-body
    localization in an Anderson insulator. Physical Review B. 105(22), L220203.
  mla: Brighi, Pietro, et al. “Propagation of Many-Body Localization in an Anderson
    Insulator.” <i>Physical Review B</i>, vol. 105, no. 22, L220203, American Physical
    Society, 2022, doi:<a href="https://doi.org/10.1103/physrevb.105.l220203">10.1103/physrevb.105.l220203</a>.
  short: P. Brighi, A.A. Michailidis, D.A. Abanin, M. Serbyn, Physical Review B 105
    (2022).
date_created: 2022-06-29T20:20:47Z
date_published: 2022-06-27T00:00:00Z
date_updated: 2023-08-03T07:23:52Z
day: '27'
department:
- _id: MaSe
doi: 10.1103/physrevb.105.l220203
ec_funded: 1
external_id:
  arxiv:
  - '2109.07332'
  isi:
  - '000823050000012'
intvolume: '       105'
isi: 1
issue: '22'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: ' https://doi.org/10.48550/arXiv.2109.07332'
month: '06'
oa: 1
oa_version: Preprint
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '850899'
  name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication: Physical Review B
publication_identifier:
  eissn:
  - 2469-9969
  issn:
  - 2469-9950
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
  record:
  - id: '12732'
    relation: dissertation_contains
    status: public
status: public
title: Propagation of many-body localization in an Anderson insulator
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 105
year: '2022'
...
---
_id: '12750'
abstract:
- lang: eng
  text: Quantum kinetically constrained models have recently attracted significant
    attention due to their anomalous dynamics and thermalization. In this work, we
    introduce a hitherto unexplored family of kinetically constrained models featuring
    a conserved particle number and strong inversion-symmetry breaking due to facilitated
    hopping. We demonstrate that these models provide a generic example of so-called
    quantum Hilbert space fragmentation, that is manifested in disconnected sectors
    in the Hilbert space that are not apparent in the computational basis. Quantum
    Hilbert space fragmentation leads to an exponential in system size number of eigenstates
    with exactly zero entanglement entropy across several bipartite cuts. These eigenstates
    can be probed dynamically using quenches from simple initial product states. In
    addition, we study the particle spreading under unitary dynamics launched from
    the domain wall state, and find faster than diffusive dynamics at high particle
    densities, that crosses over into logarithmically slow relaxation at smaller densities.
    Using a classically simulable cellular automaton, we reproduce the logarithmic
    dynamics observed in the quantum case. Our work suggests that particle conserving
    constrained models with inversion symmetry breaking realize so far unexplored
    universality classes of dynamics and invite their further theoretical and experimental
    studies.
article_number: '2210.15607'
article_processing_charge: No
arxiv: 1
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
- first_name: Marko
  full_name: Ljubotina, Marko
  id: F75EE9BE-5C90-11EA-905D-16643DDC885E
  last_name: Ljubotina
  orcid: 0000-0003-0038-7068
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Brighi P, Ljubotina M, Serbyn M. Hilbert space fragmentation and slow dynamics
    in particle-conserving quantum East models. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2210.15607">10.48550/arXiv.2210.15607</a>
  apa: Brighi, P., Ljubotina, M., &#38; Serbyn, M. (n.d.). Hilbert space fragmentation
    and slow dynamics in particle-conserving quantum East models. <i>arXiv</i>. <a
    href="https://doi.org/10.48550/arXiv.2210.15607">https://doi.org/10.48550/arXiv.2210.15607</a>
  chicago: Brighi, Pietro, Marko Ljubotina, and Maksym Serbyn. “Hilbert Space Fragmentation
    and Slow Dynamics in Particle-Conserving Quantum East Models.” <i>ArXiv</i>, n.d.
    <a href="https://doi.org/10.48550/arXiv.2210.15607">https://doi.org/10.48550/arXiv.2210.15607</a>.
  ieee: P. Brighi, M. Ljubotina, and M. Serbyn, “Hilbert space fragmentation and slow
    dynamics in particle-conserving quantum East models,” <i>arXiv</i>. .
  ista: Brighi P, Ljubotina M, Serbyn M. Hilbert space fragmentation and slow dynamics
    in particle-conserving quantum East models. arXiv, 2210.15607.
  mla: Brighi, Pietro, et al. “Hilbert Space Fragmentation and Slow Dynamics in Particle-Conserving
    Quantum East Models.” <i>ArXiv</i>, 2210.15607, doi:<a href="https://doi.org/10.48550/arXiv.2210.15607">10.48550/arXiv.2210.15607</a>.
  short: P. Brighi, M. Ljubotina, M. Serbyn, ArXiv (n.d.).
date_created: 2023-03-23T14:33:13Z
date_published: 2022-11-07T00:00:00Z
date_updated: 2023-09-20T10:46:29Z
day: '07'
department:
- _id: GradSch
- _id: MaSe
doi: 10.48550/arXiv.2210.15607
external_id:
  arxiv:
  - '2210.15607'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2210.15607
month: '11'
oa: 1
oa_version: Preprint
publication: arXiv
publication_status: submitted
related_material:
  record:
  - id: '12732'
    relation: dissertation_contains
    status: public
  - id: '14334'
    relation: later_version
    status: public
status: public
title: Hilbert space fragmentation and slow dynamics in particle-conserving quantum
  East models
tmp:
  image: /images/cc_by_nc_sa.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
    BY-NC-SA 4.0)
  short: CC BY-NC-SA (4.0)
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2022'
...
---
_id: '8308'
abstract:
- lang: eng
  text: 'Many-body localization provides a mechanism to avoid thermalization in isolated
    interacting quantum systems. The breakdown of thermalization may be complete,
    when all eigenstates in the many-body spectrum become localized, or partial, when
    the so-called many-body mobility edge separates localized and delocalized parts
    of the spectrum. Previously, De Roeck et al. [Phys. Rev. B 93, 014203 (2016)]
    suggested a possible instability of the many-body mobility edge in energy density.
    The local ergodic regions—so-called “bubbles”—resonantly spread throughout the
    system, leading to delocalization. In order to study such instability mechanism,
    in this work we design a model featuring many-body mobility edge in particle density:
    the states at small particle density are localized, while increasing the density
    of particles leads to delocalization. Using numerical simulations with matrix
    product states, we demonstrate the stability of many-body localization with respect
    to small bubbles in large dilute systems for experimentally relevant timescales.
    In addition, we demonstrate that processes where the bubble spreads are favored
    over processes that lead to resonant tunneling, suggesting a possible mechanism
    behind the observed stability of many-body mobility edge. We conclude by proposing
    experiments to probe particle density mobility edge in the Bose-Hubbard model.'
acknowledgement: 'Acknowledgments. We acknowledge useful discussions with W. De Roeck
  and A. Michailidis. P.B. was supported by the European Union''s Horizon 2020 research
  and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 665385.
  D.A. was supported by the Swiss National Science Foundation. M.S. was supported
  by European Research Council (ERC) under the European Union''s Horizon 2020 research
  and innovation program (Grant Agreement No. 850899). This work benefited from visits
  to KITP, supported by the National Science Foundation under Grant No. NSF PHY-1748958
  and from the program “Thermalization, Many Body Localization and Hydrodynamics”
  at International Centre for Theoretical Sciences (Code: ICTS/hydrodynamics2019/11).'
article_number: 060202(R)
article_processing_charge: No
article_type: original
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
- first_name: Dmitry A.
  full_name: Abanin, Dmitry A.
  last_name: Abanin
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Brighi P, Abanin DA, Serbyn M. Stability of mobility edges in disordered interacting
    systems. <i>Physical Review B</i>. 2020;102(6). doi:<a href="https://doi.org/10.1103/physrevb.102.060202">10.1103/physrevb.102.060202</a>
  apa: Brighi, P., Abanin, D. A., &#38; Serbyn, M. (2020). Stability of mobility edges
    in disordered interacting systems. <i>Physical Review B</i>. American Physical
    Society. <a href="https://doi.org/10.1103/physrevb.102.060202">https://doi.org/10.1103/physrevb.102.060202</a>
  chicago: Brighi, Pietro, Dmitry A. Abanin, and Maksym Serbyn. “Stability of Mobility
    Edges in Disordered Interacting Systems.” <i>Physical Review B</i>. American Physical
    Society, 2020. <a href="https://doi.org/10.1103/physrevb.102.060202">https://doi.org/10.1103/physrevb.102.060202</a>.
  ieee: P. Brighi, D. A. Abanin, and M. Serbyn, “Stability of mobility edges in disordered
    interacting systems,” <i>Physical Review B</i>, vol. 102, no. 6. American Physical
    Society, 2020.
  ista: Brighi P, Abanin DA, Serbyn M. 2020. Stability of mobility edges in disordered
    interacting systems. Physical Review B. 102(6), 060202(R).
  mla: Brighi, Pietro, et al. “Stability of Mobility Edges in Disordered Interacting
    Systems.” <i>Physical Review B</i>, vol. 102, no. 6, 060202(R), American Physical
    Society, 2020, doi:<a href="https://doi.org/10.1103/physrevb.102.060202">10.1103/physrevb.102.060202</a>.
  short: P. Brighi, D.A. Abanin, M. Serbyn, Physical Review B 102 (2020).
date_created: 2020-08-26T19:27:42Z
date_published: 2020-08-26T00:00:00Z
date_updated: 2023-08-24T14:20:21Z
day: '26'
ddc:
- '530'
department:
- _id: MaSe
doi: 10.1103/physrevb.102.060202
ec_funded: 1
external_id:
  isi:
  - '000562628300001'
file:
- access_level: open_access
  checksum: 716442fa7861323fcc80b93718ca009c
  content_type: application/pdf
  creator: mserbyn
  date_created: 2020-08-26T19:28:55Z
  date_updated: 2020-08-26T19:28:55Z
  file_id: '8309'
  file_name: PhysRevB.102.060202.pdf
  file_size: 488825
  relation: main_file
  success: 1
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  date_created: 2020-08-26T19:29:00Z
  date_updated: 2020-08-26T19:29:00Z
  file_id: '8310'
  file_name: Supplementary-mbme.pdf
  file_size: 711405
  relation: main_file
  success: 1
file_date_updated: 2020-08-26T19:29:00Z
has_accepted_license: '1'
intvolume: '       102'
isi: 1
issue: '6'
language:
- iso: eng
month: '08'
oa: 1
oa_version: None
project:
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '665385'
  name: International IST Doctoral Program
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '850899'
  name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication: Physical Review B
publication_identifier:
  eissn:
  - 2469-9969
  issn:
  - 2469-9950
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
  record:
  - id: '12732'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: Stability of mobility edges in disordered interacting systems
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 102
year: '2020'
...
---
_id: '7200'
abstract:
- lang: eng
  text: Recent scanning tunneling microscopy experiments in NbN thin disordered superconducting
    films found an emergent inhomogeneity at the scale of tens of nanometers. This
    inhomogeneity is mirrored by an apparent dimensional crossover in the paraconductivity
    measured in transport above the superconducting critical temperature Tc. This
    behavior was interpreted in terms of an anomalous diffusion of fluctuating Cooper
    pairs that display a quasiconfinement (i.e., a slowing down of their diffusive
    dynamics) on length scales shorter than the inhomogeneity identified by tunneling
    experiments. Here, we assume this anomalous diffusive behavior of fluctuating
    Cooper pairs and calculate the effect of these fluctuations on the electron density
    of states above Tc. We find that the density of states is substantially suppressed
    up to temperatures well above Tc. This behavior, which is closely reminiscent
    of a pseudogap, only arises from the anomalous diffusion of fluctuating Cooper
    pairs in the absence of stable preformed pairs, setting the stage for an intermediate
    behavior between the two common paradigms in the superconducting-insulator transition,
    namely, the localization of Cooper pairs (the so-called bosonic scenario) and
    the breaking of Cooper pairs into unpaired electrons due to strong disorder (the
    so-called fermionic scenario).
article_number: '174518'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Pietro
  full_name: Brighi, Pietro
  id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
  last_name: Brighi
  orcid: 0000-0002-7969-2729
- first_name: Marco
  full_name: Grilli, Marco
  last_name: Grilli
- first_name: Brigitte
  full_name: Leridon, Brigitte
  last_name: Leridon
- first_name: Sergio
  full_name: Caprara, Sergio
  last_name: Caprara
citation:
  ama: Brighi P, Grilli M, Leridon B, Caprara S. Effect of anomalous diffusion of
    fluctuating Cooper pairs on the density of states of superconducting NbN thin
    films. <i>Physical Review B</i>. 2019;100(17). doi:<a href="https://doi.org/10.1103/PhysRevB.100.174518">10.1103/PhysRevB.100.174518</a>
  apa: Brighi, P., Grilli, M., Leridon, B., &#38; Caprara, S. (2019). Effect of anomalous
    diffusion of fluctuating Cooper pairs on the density of states of superconducting
    NbN thin films. <i>Physical Review B</i>. American Physical Society. <a href="https://doi.org/10.1103/PhysRevB.100.174518">https://doi.org/10.1103/PhysRevB.100.174518</a>
  chicago: Brighi, Pietro, Marco Grilli, Brigitte Leridon, and Sergio Caprara. “Effect
    of Anomalous Diffusion of Fluctuating Cooper Pairs on the Density of States of
    Superconducting NbN Thin Films.” <i>Physical Review B</i>. American Physical Society,
    2019. <a href="https://doi.org/10.1103/PhysRevB.100.174518">https://doi.org/10.1103/PhysRevB.100.174518</a>.
  ieee: P. Brighi, M. Grilli, B. Leridon, and S. Caprara, “Effect of anomalous diffusion
    of fluctuating Cooper pairs on the density of states of superconducting NbN thin
    films,” <i>Physical Review B</i>, vol. 100, no. 17. American Physical Society,
    2019.
  ista: Brighi P, Grilli M, Leridon B, Caprara S. 2019. Effect of anomalous diffusion
    of fluctuating Cooper pairs on the density of states of superconducting NbN thin
    films. Physical Review B. 100(17), 174518.
  mla: Brighi, Pietro, et al. “Effect of Anomalous Diffusion of Fluctuating Cooper
    Pairs on the Density of States of Superconducting NbN Thin Films.” <i>Physical
    Review B</i>, vol. 100, no. 17, 174518, American Physical Society, 2019, doi:<a
    href="https://doi.org/10.1103/PhysRevB.100.174518">10.1103/PhysRevB.100.174518</a>.
  short: P. Brighi, M. Grilli, B. Leridon, S. Caprara, Physical Review B 100 (2019).
date_created: 2019-12-22T23:00:41Z
date_published: 2019-11-25T00:00:00Z
date_updated: 2024-02-28T13:14:08Z
day: '25'
department:
- _id: MaSe
doi: 10.1103/PhysRevB.100.174518
external_id:
  arxiv:
  - '1907.13579'
  isi:
  - '000498845700006'
intvolume: '       100'
isi: 1
issue: '17'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1907.13579
month: '11'
oa: 1
oa_version: Preprint
publication: Physical Review B
publication_identifier:
  eissn:
  - 2469-9969
  issn:
  - 2469-9950
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Effect of anomalous diffusion of fluctuating Cooper pairs on the density of
  states of superconducting NbN thin films
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 100
year: '2019'
...
