---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '19371'
abstract:
- lang: eng
text: We investigate a molecular quantum rotor in a two-dimensional Bose-Einstein
condensate. The focus is on studying the angulon quasiparticle concept in the
crossover from few- to many-body physics. To this end, we formulate the problem
in real space and solve it with a mean-field approach in the frame co-rotating
with the impurity. We show that the system starts to feature angulon characteristics
when the size of the bosonic cloud is large enough to screen the rotor. More importantly,
we demonstrate the departure from the angulon picture for large system sizes or
large angular momenta where the properties of the system are determined by collective
excitations of the Bose gas.
acknowledgement: "We thank Fabian Brauneis, Arthur Christianen and Pietro Massignan
for useful discussions. M. S. and A. G. V. would like to thank the Institut Henri
Poincaré\r\n(UAR 839 CNRS-Sorbonne Université) and the LabEx CARMIN (ANR-10-LABX-59-01)
for\r\ntheir support and hospitality during the final stages of completion of this
work. M.S.\r\nand M.T. acknowledge the National Science Centre, Poland, within Sonata
Bis Grant No.\r\n2020/38/E/ST2/00564. M.L. acknowledges support by the European
Research Council (ERC)\r\nStarting Grant No.801770 (ANGULON). M.S. acknowledges
the National Science Centre,\r\nPoland, within Preludium Grant No. 2023/49/N/ST2/03820.
We gratefully acknowledge\r\nPoland’s high-performance Infrastructure PLGrid ACK
Cyfronet AGH for providing computer\r\nfacilities and support within computational
grant no PLG/2023/016878."
article_number: '059'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Michał
full_name: Suchorowski, Michał
last_name: Suchorowski
- first_name: Alina
full_name: Badamshina, Alina
last_name: Badamshina
- first_name: Mikhail
full_name: Lemeshko, Mikhail
id: 37CB05FA-F248-11E8-B48F-1D18A9856A87
last_name: Lemeshko
orcid: 0000-0002-6990-7802
- first_name: Michał
full_name: Tomza, Michał
last_name: Tomza
- first_name: Artem
full_name: Volosniev, Artem
id: 37D278BC-F248-11E8-B48F-1D18A9856A87
last_name: Volosniev
orcid: 0000-0003-0393-5525
citation:
ama: Suchorowski M, Badamshina A, Lemeshko M, Tomza M, Volosniev A. Quantum rotor
in a two-dimensional mesoscopic Bose gas. SciPost Physics. 2025;18(2).
doi:10.21468/SciPostPhys.18.2.059
apa: Suchorowski, M., Badamshina, A., Lemeshko, M., Tomza, M., & Volosniev,
A. (2025). Quantum rotor in a two-dimensional mesoscopic Bose gas. SciPost
Physics. SciPost Foundation. https://doi.org/10.21468/SciPostPhys.18.2.059
chicago: Suchorowski, Michał, Alina Badamshina, Mikhail Lemeshko, Michał Tomza,
and Artem Volosniev. “Quantum Rotor in a Two-Dimensional Mesoscopic Bose Gas.”
SciPost Physics. SciPost Foundation, 2025. https://doi.org/10.21468/SciPostPhys.18.2.059.
ieee: M. Suchorowski, A. Badamshina, M. Lemeshko, M. Tomza, and A. Volosniev, “Quantum
rotor in a two-dimensional mesoscopic Bose gas,” SciPost Physics, vol.
18, no. 2. SciPost Foundation, 2025.
ista: Suchorowski M, Badamshina A, Lemeshko M, Tomza M, Volosniev A. 2025. Quantum
rotor in a two-dimensional mesoscopic Bose gas. SciPost Physics. 18(2), 059.
mla: Suchorowski, Michał, et al. “Quantum Rotor in a Two-Dimensional Mesoscopic
Bose Gas.” SciPost Physics, vol. 18, no. 2, 059, SciPost Foundation, 2025,
doi:10.21468/SciPostPhys.18.2.059.
short: M. Suchorowski, A. Badamshina, M. Lemeshko, M. Tomza, A. Volosniev, SciPost
Physics 18 (2025).
corr_author: '1'
date_created: 2025-03-09T23:01:28Z
date_published: 2025-02-19T00:00:00Z
date_updated: 2025-04-14T07:48:55Z
day: '19'
ddc:
- '530'
department:
- _id: MiLe
doi: 10.21468/SciPostPhys.18.2.059
ec_funded: 1
external_id:
arxiv:
- '2407.06046'
file:
- access_level: open_access
checksum: 7bed8c68c36d495540491bd0579e33e4
content_type: application/pdf
creator: dernst
date_created: 2025-03-10T07:08:21Z
date_updated: 2025-03-10T07:08:21Z
file_id: '19376'
file_name: 2025_SciPostPhys_Suchorowski.pdf
file_size: 1124066
relation: main_file
success: 1
file_date_updated: 2025-03-10T07:08:21Z
has_accepted_license: '1'
intvolume: ' 18'
issue: '2'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
project:
- _id: 2688CF98-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '801770'
name: 'Angulon: physics and applications of a new quasiparticle'
publication: SciPost Physics
publication_identifier:
eissn:
- 2542-4653
publication_status: published
publisher: SciPost Foundation
quality_controlled: '1'
scopus_import: '1'
status: public
title: Quantum rotor in a two-dimensional mesoscopic Bose gas
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: 18
year: '2025'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '20003'
abstract:
- lang: eng
text: The problem of mobile impurities in quantum baths is of fundamental importance
in many-body physics. There has recently been significant progress regarding our
understanding of this due to cold atom experiments, but so far it has mainly been
concerned with cases where the bath has no or only weak interactions, or the impurity
interacts weakly with the bath. Here, we address this gap by developing a new
theoretical framework for exploring a mobile impurity interacting strongly with
a highly correlated bath of bosons in the quantum critical regime of a Mott insulator
(MI) to superfluid (SF) quantum phase transition. Our framework is based on a
powerful quantum Gutzwiller (QGW) description of the bosonic bath combined with
diagrammatic field theory for the impurity-bath interactions. By resumming a selected
class of diagrams to infinite order, a rich picture emerges where the impurity
is dressed by the fundamental modes of the bath, which change character from gapped
particle-hole excitations in the MI to Higgs and gapless Goldstone modes in the
SF. This gives rise to the existence of several quasiparticle (polaron) branches
with properties reflecting the strongly correlated environment. In particular,
one polaron branch exhibits a sharp cusp in its energy, while a new ground-state
polaron emerges at the O(2) quantum phase transition point for integer filling,
which reflects the nonanalytic behavior at the transition and the appearance of
the Goldstone mode in the SF phase. Smooth versions of these features are inherited
in the polaron spectrum away from integer filling due to the influence of Mott
physics on the bosonic bath. We furthermore compare our diagrammatic results with
quantum Monte Carlo calculations, obtaining excellent agreement. This accuracy
is quite remarkable for such a highly non-trivial case of strong interactions
between the impurity and bosons in a maximally correlated quantum critical regime,
and it establishes the utility of our framework. Finally, our results show how
impurities can be used as quantum sensors and highlight fundamental differences
between experiments performed at a fixed particle number or a fixed chemical potential.
article_number: '002'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Ragheed
full_name: Al Hyder, Ragheed
id: d1c405be-ae15-11ed-8510-ccf53278162e
last_name: Al Hyder
- first_name: Victor E.
full_name: Colussi, Victor E.
last_name: Colussi
- first_name: Matija
full_name: Čufar, Matija
last_name: Čufar
- first_name: Joachim
full_name: Brand, Joachim
last_name: Brand
- first_name: Alessio
full_name: Recati, Alessio
last_name: Recati
- first_name: Georg M.
full_name: Bruun, Georg M.
last_name: Bruun
citation:
ama: Al Hyder R, Colussi VE, Čufar M, Brand J, Recati A, Bruun GM. Lattice Bose
polarons at strong coupling and quantum criticality. Scipost Physics. 2025;19(1).
doi:10.21468/SciPostPhys.19.1.002
apa: Al Hyder, R., Colussi, V. E., Čufar, M., Brand, J., Recati, A., & Bruun,
G. M. (2025). Lattice Bose polarons at strong coupling and quantum criticality.
Scipost Physics. SciPost Foundation. https://doi.org/10.21468/SciPostPhys.19.1.002
chicago: Al Hyder, Ragheed, Victor E. Colussi, Matija Čufar, Joachim Brand, Alessio
Recati, and Georg M. Bruun. “Lattice Bose Polarons at Strong Coupling and Quantum
Criticality.” Scipost Physics. SciPost Foundation, 2025. https://doi.org/10.21468/SciPostPhys.19.1.002.
ieee: R. Al Hyder, V. E. Colussi, M. Čufar, J. Brand, A. Recati, and G. M. Bruun,
“Lattice Bose polarons at strong coupling and quantum criticality,” Scipost
Physics, vol. 19, no. 1. SciPost Foundation, 2025.
ista: Al Hyder R, Colussi VE, Čufar M, Brand J, Recati A, Bruun GM. 2025. Lattice
Bose polarons at strong coupling and quantum criticality. Scipost Physics. 19(1),
002.
mla: Al Hyder, Ragheed, et al. “Lattice Bose Polarons at Strong Coupling and Quantum
Criticality.” Scipost Physics, vol. 19, no. 1, 002, SciPost Foundation,
2025, doi:10.21468/SciPostPhys.19.1.002.
short: R. Al Hyder, V.E. Colussi, M. Čufar, J. Brand, A. Recati, G.M. Bruun, Scipost
Physics 19 (2025).
corr_author: '1'
date_created: 2025-07-13T22:01:22Z
date_published: 2025-07-01T00:00:00Z
date_updated: 2025-09-30T14:00:26Z
day: '01'
ddc:
- '530'
department:
- _id: MiLe
doi: 10.21468/SciPostPhys.19.1.002
external_id:
arxiv:
- '2412.07597'
isi:
- '001523515000002'
file:
- access_level: open_access
checksum: a2ce71aab685b7ea29e7abcf81e2fcc1
content_type: application/pdf
creator: dernst
date_created: 2025-07-14T07:02:38Z
date_updated: 2025-07-14T07:02:38Z
file_id: '20014'
file_name: 2025_SciPostPhys_AlHyder.pdf
file_size: 9769204
relation: main_file
success: 1
file_date_updated: 2025-07-14T07:02:38Z
has_accepted_license: '1'
intvolume: ' 19'
isi: 1
issue: '1'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
publication: Scipost Physics
publication_identifier:
eissn:
- 2542-4653
publication_status: published
publisher: SciPost Foundation
quality_controlled: '1'
scopus_import: '1'
status: public
title: Lattice Bose polarons at strong coupling and quantum criticality
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: 19
year: '2025'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: diamond
PlanS_conform: '1'
_id: '20666'
abstract:
- lang: eng
text: We theoretically investigate the stationary properties of a spin-1/2 impurity
immersed in a one-dimensional confined Bose gas. In particular, we consider coherently
coupled spin states with an external field, where only one spin component interacts
with the bath, enabling light dressing of the impurity and spin-dependent bath-impurity
interactions. Through detailed comparisons with ab-initio many-body simulations,
we demonstrate that the composite system is accurately described by a simplified
effective Hamiltonian. The latter builds upon previously developed effective potential
approaches in the absence of light dressing. It can be used to extract the impurity
energy, residue, effective mass, and anharmonicity induced by the phononic dressing.
Light-dressing is shown to increase the polaron residue, undressing the impurity
from phononic excitations because of strong spin coupling. For strong repulsions,
previously shown to trigger dynamical Bose polaron decay (a phenomenon called
temporal orthogonality catastrophe), it is explained that strong light-dressing
stabilizes a repulsive polaron-dressed state. Our results establish the effective
Hamiltonian framework as a powerful tool for exploring strongly interacting polaronic
systems and corroborating forthcoming experimental realizations.
acknowledgement: "G.M.K. has received funding by the Austrian Science Fund (FWF)\r\n[DOI:
10.55776/F1004]. S.I.M acknowledges support from the Missouri University of Science
and Technology, Department of Physics, Startup fund. F.G. acknowledges funding by
the\r\nDeutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s
Excellence Strategy – EXC-2111 — 390814868. H.R.S. acknowledges support for ITAMP
by the\r\nNSF. P.S. acknowledges funding by the Cluster of Excellence “Advanced
Imaging of Matter” of\r\nthe Deutsche Forschungsgemeinschaft (DFG) - EXC 2056 -
project ID 390715994."
article_number: '093'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Georgios
full_name: Koutentakis, Georgios
id: d7b23d3a-9e21-11ec-b482-f76739596b95
last_name: Koutentakis
- first_name: S. I.
full_name: Mistakidis, S. I.
last_name: Mistakidis
- first_name: F.
full_name: Grusdt, F.
last_name: Grusdt
- first_name: H. R.
full_name: Sadeghpour, H. R.
last_name: Sadeghpour
- first_name: P.
full_name: Schmelcher, P.
last_name: Schmelcher
citation:
ama: Koutentakis G, Mistakidis SI, Grusdt F, Sadeghpour HR, Schmelcher P. Competition
of light-and phonon-dressing in microwave-dressed Bose polarons. Scipost Physics.
2025;19(4). doi:10.21468/SciPostPhys.19.4.093
apa: Koutentakis, G., Mistakidis, S. I., Grusdt, F., Sadeghpour, H. R., & Schmelcher,
P. (2025). Competition of light-and phonon-dressing in microwave-dressed Bose
polarons. Scipost Physics. SciPost Foundation. https://doi.org/10.21468/SciPostPhys.19.4.093
chicago: Koutentakis, Georgios, S. I. Mistakidis, F. Grusdt, H. R. Sadeghpour, and
P. Schmelcher. “Competition of Light-and Phonon-Dressing in Microwave-Dressed
Bose Polarons.” Scipost Physics. SciPost Foundation, 2025. https://doi.org/10.21468/SciPostPhys.19.4.093.
ieee: G. Koutentakis, S. I. Mistakidis, F. Grusdt, H. R. Sadeghpour, and P. Schmelcher,
“Competition of light-and phonon-dressing in microwave-dressed Bose polarons,”
Scipost Physics, vol. 19, no. 4. SciPost Foundation, 2025.
ista: Koutentakis G, Mistakidis SI, Grusdt F, Sadeghpour HR, Schmelcher P. 2025.
Competition of light-and phonon-dressing in microwave-dressed Bose polarons. Scipost
Physics. 19(4), 093.
mla: Koutentakis, Georgios, et al. “Competition of Light-and Phonon-Dressing in
Microwave-Dressed Bose Polarons.” Scipost Physics, vol. 19, no. 4, 093,
SciPost Foundation, 2025, doi:10.21468/SciPostPhys.19.4.093.
short: G. Koutentakis, S.I. Mistakidis, F. Grusdt, H.R. Sadeghpour, P. Schmelcher,
Scipost Physics 19 (2025).
corr_author: '1'
date_created: 2025-11-23T23:01:39Z
date_published: 2025-10-01T00:00:00Z
date_updated: 2025-12-01T15:22:01Z
day: '01'
ddc:
- '530'
department:
- _id: MiLe
doi: 10.21468/SciPostPhys.19.4.093
external_id:
arxiv:
- '2504.03411'
isi:
- '001593017800002'
file:
- access_level: open_access
checksum: 04d0e47ba66c63737431d7b8ed1df4bc
content_type: application/pdf
creator: dernst
date_created: 2025-11-24T08:42:42Z
date_updated: 2025-11-24T08:42:42Z
file_id: '20673'
file_name: 2025_SciPostPhys_Koutentakis.pdf
file_size: 1725787
relation: main_file
success: 1
file_date_updated: 2025-11-24T08:42:42Z
has_accepted_license: '1'
intvolume: ' 19'
isi: 1
issue: '4'
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
project:
- _id: 7c040762-9f16-11ee-852c-dd79eeee4ab3
grant_number: F100403
name: Coherent Optical Metrology Beyond Electric-Dipole-Allowed Transitions
publication: Scipost Physics
publication_identifier:
eissn:
- 2542-4653
publication_status: published
publisher: SciPost Foundation
quality_controlled: '1'
scopus_import: '1'
status: public
title: Competition of light-and phonon-dressing in microwave-dressed Bose polarons
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: 19
year: '2025'
...
---
_id: '9769'
abstract:
- lang: eng
text: A few years ago, flow equations were introduced as a technique for calculating
the ground-state energies of cold Bose gases with and without impurities. In this
paper, we extend this approach to compute observables other than the energy. As
an example, we calculate the densities, and phase fluctuations of one-dimensional
Bose gases with one and two impurities. For a single mobile impurity, we use flow
equations to validate the mean-field results obtained upon the Lee-Low-Pines transformation.
We show that the mean-field approximation is accurate for all values of the boson-impurity
interaction strength as long as the phase coherence length is much larger than
the healing length of the condensate. For two static impurities, we calculate
impurity-impurity interactions induced by the Bose gas. We find that leading order
perturbation theory fails when boson-impurity interactions are stronger than boson-boson
interactions. The mean-field approximation reproduces the flow equation results
for all values of the boson-impurity interaction strength as long as boson-boson
interactions are weak.
acknowledgement: We thank Matthias Heinz and Volker Karle for helpful comments on
the manuscript; Zoran Ristivojevic for useful correspondence regarding mean-field
calculations of induced impurity-impurity interactions; Fabian Grusdt for sharing
with us the data for the densities presented in Ref. [14]. This work has received
funding from the DFG Project No. 413495248 [VO 2437/1-1] (F. B., H.-W. H., A. G.
V.) and European Union’s Horizon 2020 research and innovation programme under the
Marie Skłodowska-Curie Grant Agreement No. 754411 (A. G. V.). M. L. acknowledges
support by the European Research Council (ERC) Starting Grant No. 801770 (ANGULON).
H.-W.H. thanks the ECT* for hospitality during the workshop “Universal physics in
Many-Body Quantum Systems – From Atoms to Quarks". This infrastructure is part of
a project that has received funding from the European Union’s Horizon 2020 research
and innovation programme under grant agreement No 824093. H.-W.H. was supported
by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID
279384907 - SFB 1245.
article_number: '008'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Fabian
full_name: Brauneis, Fabian
last_name: Brauneis
- first_name: Hans-Werner
full_name: Hammer, Hans-Werner
last_name: Hammer
- first_name: Mikhail
full_name: Lemeshko, Mikhail
id: 37CB05FA-F248-11E8-B48F-1D18A9856A87
last_name: Lemeshko
orcid: 0000-0002-6990-7802
- first_name: Artem
full_name: Volosniev, Artem
id: 37D278BC-F248-11E8-B48F-1D18A9856A87
last_name: Volosniev
orcid: 0000-0003-0393-5525
citation:
ama: 'Brauneis F, Hammer H-W, Lemeshko M, Volosniev A. Impurities in a one-dimensional
Bose gas: The flow equation approach. SciPost Physics. 2021;11(1). doi:10.21468/scipostphys.11.1.008'
apa: 'Brauneis, F., Hammer, H.-W., Lemeshko, M., & Volosniev, A. (2021). Impurities
in a one-dimensional Bose gas: The flow equation approach. SciPost Physics.
SciPost Foundation. https://doi.org/10.21468/scipostphys.11.1.008'
chicago: 'Brauneis, Fabian, Hans-Werner Hammer, Mikhail Lemeshko, and Artem Volosniev.
“Impurities in a One-Dimensional Bose Gas: The Flow Equation Approach.” SciPost
Physics. SciPost Foundation, 2021. https://doi.org/10.21468/scipostphys.11.1.008.'
ieee: 'F. Brauneis, H.-W. Hammer, M. Lemeshko, and A. Volosniev, “Impurities in
a one-dimensional Bose gas: The flow equation approach,” SciPost Physics,
vol. 11, no. 1. SciPost Foundation, 2021.'
ista: 'Brauneis F, Hammer H-W, Lemeshko M, Volosniev A. 2021. Impurities in a one-dimensional
Bose gas: The flow equation approach. SciPost Physics. 11(1), 008.'
mla: 'Brauneis, Fabian, et al. “Impurities in a One-Dimensional Bose Gas: The Flow
Equation Approach.” SciPost Physics, vol. 11, no. 1, 008, SciPost Foundation,
2021, doi:10.21468/scipostphys.11.1.008.'
short: F. Brauneis, H.-W. Hammer, M. Lemeshko, A. Volosniev, SciPost Physics 11
(2021).
date_created: 2021-08-04T15:00:55Z
date_published: 2021-07-13T00:00:00Z
date_updated: 2025-05-14T10:51:56Z
day: '13'
ddc:
- '530'
department:
- _id: MiLe
doi: 10.21468/scipostphys.11.1.008
ec_funded: 1
external_id:
arxiv:
- '2101.10958'
isi:
- '000680039500013'
file:
- access_level: open_access
checksum: eaa847346b1a023d97bbb291779610ed
content_type: application/pdf
creator: asandaue
date_created: 2021-08-10T11:44:59Z
date_updated: 2021-08-10T11:44:59Z
file_id: '9875'
file_name: 2021_SciPostPhysics_Brauneis.pdf
file_size: 1085300
relation: main_file
success: 1
file_date_updated: 2021-08-10T11:44:59Z
has_accepted_license: '1'
intvolume: ' 11'
isi: 1
issue: '1'
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '754411'
name: ISTplus - Postdoctoral Fellowships
- _id: 2688CF98-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '801770'
name: 'Angulon: physics and applications of a new quasiparticle'
publication: SciPost Physics
publication_identifier:
eissn:
- 2542-4653
publication_status: published
publisher: SciPost Foundation
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Impurities in a one-dimensional Bose gas: The flow equation approach'
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: 11
year: '2021'
...