[{"file":[{"creator":"dernst","access_level":"open_access","content_type":"application/pdf","success":1,"checksum":"7bed8c68c36d495540491bd0579e33e4","file_name":"2025_SciPostPhys_Suchorowski.pdf","relation":"main_file","date_created":"2025-03-10T07:08:21Z","date_updated":"2025-03-10T07:08:21Z","file_id":"19376","file_size":1124066}],"status":"public","external_id":{"arxiv":["2407.06046"]},"publisher":"SciPost Foundation","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_processing_charge":"Yes","oa":1,"issue":"2","arxiv":1,"corr_author":"1","date_published":"2025-02-19T00:00:00Z","_id":"19371","oa_version":"Published Version","volume":18,"article_number":"059","article_type":"original","file_date_updated":"2025-03-10T07:08:21Z","title":"Quantum rotor in a two-dimensional mesoscopic Bose gas","date_updated":"2025-04-14T07:48:55Z","license":"https://creativecommons.org/licenses/by/4.0/","ec_funded":1,"project":[{"call_identifier":"H2020","grant_number":"801770","_id":"2688CF98-B435-11E9-9278-68D0E5697425","name":"Angulon: physics and applications of a new quasiparticle"}],"doi":"10.21468/SciPostPhys.18.2.059","scopus_import":"1","OA_type":"gold","has_accepted_license":"1","author":[{"first_name":"Michał","last_name":"Suchorowski","full_name":"Suchorowski, Michał"},{"first_name":"Alina","last_name":"Badamshina","full_name":"Badamshina, Alina"},{"first_name":"Mikhail","orcid":"0000-0002-6990-7802","full_name":"Lemeshko, Mikhail","last_name":"Lemeshko","id":"37CB05FA-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Michał","last_name":"Tomza","full_name":"Tomza, Michał"},{"orcid":"0000-0003-0393-5525","first_name":"Artem","id":"37D278BC-F248-11E8-B48F-1D18A9856A87","full_name":"Volosniev, Artem","last_name":"Volosniev"}],"day":"19","ddc":["530"],"language":[{"iso":"eng"}],"department":[{"_id":"MiLe"}],"type":"journal_article","publication":"SciPost Physics","date_created":"2025-03-09T23:01:28Z","abstract":[{"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.","lang":"eng"}],"quality_controlled":"1","year":"2025","citation":{"ieee":"M. Suchorowski, A. Badamshina, M. Lemeshko, M. Tomza, and A. Volosniev, “Quantum rotor in a two-dimensional mesoscopic Bose gas,” <i>SciPost Physics</i>, vol. 18, no. 2. SciPost Foundation, 2025.","chicago":"Suchorowski, Michał, Alina Badamshina, Mikhail Lemeshko, Michał Tomza, and Artem Volosniev. “Quantum Rotor in a Two-Dimensional Mesoscopic Bose Gas.” <i>SciPost Physics</i>. SciPost Foundation, 2025. <a href=\"https://doi.org/10.21468/SciPostPhys.18.2.059\">https://doi.org/10.21468/SciPostPhys.18.2.059</a>.","ama":"Suchorowski M, Badamshina A, Lemeshko M, Tomza M, Volosniev A. Quantum rotor in a two-dimensional mesoscopic Bose gas. <i>SciPost Physics</i>. 2025;18(2). doi:<a href=\"https://doi.org/10.21468/SciPostPhys.18.2.059\">10.21468/SciPostPhys.18.2.059</a>","short":"M. Suchorowski, A. Badamshina, M. Lemeshko, M. Tomza, A. Volosniev, SciPost Physics 18 (2025).","apa":"Suchorowski, M., Badamshina, A., Lemeshko, M., Tomza, M., &#38; Volosniev, A. (2025). Quantum rotor in a two-dimensional mesoscopic Bose gas. <i>SciPost Physics</i>. SciPost Foundation. <a href=\"https://doi.org/10.21468/SciPostPhys.18.2.059\">https://doi.org/10.21468/SciPostPhys.18.2.059</a>","mla":"Suchorowski, Michał, et al. “Quantum Rotor in a Two-Dimensional Mesoscopic Bose Gas.” <i>SciPost Physics</i>, vol. 18, no. 2, 059, SciPost Foundation, 2025, doi:<a href=\"https://doi.org/10.21468/SciPostPhys.18.2.059\">10.21468/SciPostPhys.18.2.059</a>.","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."},"month":"02","OA_place":"publisher","DOAJ_listed":"1","publication_identifier":{"eissn":["2542-4653"]},"publication_status":"published","intvolume":"        18","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"}},{"publication_identifier":{"eissn":["2542-4653"]},"publication_status":"published","intvolume":"        19","tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"user_id":"317138e5-6ab7-11ef-aa6d-ffef3953e345","isi":1,"type":"journal_article","publication":"Scipost Physics","citation":{"short":"R. Al Hyder, V.E. Colussi, M. Čufar, J. Brand, A. Recati, G.M. Bruun, Scipost Physics 19 (2025).","apa":"Al Hyder, R., Colussi, V. E., Čufar, M., Brand, J., Recati, A., &#38; Bruun, G. M. (2025). Lattice Bose polarons at strong coupling and quantum criticality. <i>Scipost Physics</i>. SciPost Foundation. <a href=\"https://doi.org/10.21468/SciPostPhys.19.1.002\">https://doi.org/10.21468/SciPostPhys.19.1.002</a>","mla":"Al Hyder, Ragheed, et al. “Lattice Bose Polarons at Strong Coupling and Quantum Criticality.” <i>Scipost Physics</i>, vol. 19, no. 1, 002, SciPost Foundation, 2025, doi:<a href=\"https://doi.org/10.21468/SciPostPhys.19.1.002\">10.21468/SciPostPhys.19.1.002</a>.","ama":"Al Hyder R, Colussi VE, Čufar M, Brand J, Recati A, Bruun GM. Lattice Bose polarons at strong coupling and quantum criticality. <i>Scipost Physics</i>. 2025;19(1). doi:<a href=\"https://doi.org/10.21468/SciPostPhys.19.1.002\">10.21468/SciPostPhys.19.1.002</a>","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.","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,” <i>Scipost Physics</i>, vol. 19, no. 1. SciPost Foundation, 2025.","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.” <i>Scipost Physics</i>. SciPost Foundation, 2025. <a href=\"https://doi.org/10.21468/SciPostPhys.19.1.002\">https://doi.org/10.21468/SciPostPhys.19.1.002</a>."},"year":"2025","quality_controlled":"1","date_created":"2025-07-13T22:01:22Z","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."}],"month":"07","DOAJ_listed":"1","OA_place":"publisher","article_type":"original","file_date_updated":"2025-07-14T07:02:38Z","volume":19,"oa_version":"Published Version","article_number":"002","date_updated":"2025-09-30T14:00:26Z","title":"Lattice Bose polarons at strong coupling and quantum criticality","author":[{"first_name":"Ragheed","id":"d1c405be-ae15-11ed-8510-ccf53278162e","last_name":"Al Hyder","full_name":"Al Hyder, Ragheed"},{"first_name":"Victor E.","full_name":"Colussi, Victor E.","last_name":"Colussi"},{"full_name":"Čufar, Matija","last_name":"Čufar","first_name":"Matija"},{"first_name":"Joachim","last_name":"Brand","full_name":"Brand, Joachim"},{"first_name":"Alessio","full_name":"Recati, Alessio","last_name":"Recati"},{"first_name":"Georg M.","last_name":"Bruun","full_name":"Bruun, Georg M."}],"day":"01","ddc":["530"],"PlanS_conform":"1","scopus_import":"1","doi":"10.21468/SciPostPhys.19.1.002","OA_type":"diamond","has_accepted_license":"1","department":[{"_id":"MiLe"}],"language":[{"iso":"eng"}],"external_id":{"arxiv":["2412.07597"],"isi":["001523515000002"]},"file":[{"checksum":"a2ce71aab685b7ea29e7abcf81e2fcc1","creator":"dernst","access_level":"open_access","content_type":"application/pdf","success":1,"file_size":9769204,"file_name":"2025_SciPostPhys_AlHyder.pdf","date_updated":"2025-07-14T07:02:38Z","date_created":"2025-07-14T07:02:38Z","relation":"main_file","file_id":"20014"}],"status":"public","article_processing_charge":"No","oa":1,"issue":"1","publisher":"SciPost Foundation","corr_author":"1","arxiv":1,"_id":"20003","date_published":"2025-07-01T00:00:00Z"},{"project":[{"name":"Coherent Optical Metrology Beyond Electric-Dipole-Allowed Transitions","grant_number":"F100403","_id":"7c040762-9f16-11ee-852c-dd79eeee4ab3"}],"title":"Competition of light-and phonon-dressing in microwave-dressed Bose polarons","date_updated":"2025-12-01T15:22:01Z","article_type":"original","file_date_updated":"2025-11-24T08:42:42Z","oa_version":"Published Version","volume":19,"article_number":"093","department":[{"_id":"MiLe"}],"language":[{"iso":"eng"}],"author":[{"id":"d7b23d3a-9e21-11ec-b482-f76739596b95","full_name":"Koutentakis, Georgios","last_name":"Koutentakis","first_name":"Georgios"},{"full_name":"Mistakidis, S. I.","last_name":"Mistakidis","first_name":"S. I."},{"full_name":"Grusdt, F.","last_name":"Grusdt","first_name":"F."},{"first_name":"H. R.","last_name":"Sadeghpour","full_name":"Sadeghpour, H. R."},{"first_name":"P.","last_name":"Schmelcher","full_name":"Schmelcher, P."}],"day":"01","ddc":["530"],"PlanS_conform":"1","scopus_import":"1","doi":"10.21468/SciPostPhys.19.4.093","OA_type":"diamond","has_accepted_license":"1","article_processing_charge":"No","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.","oa":1,"issue":"4","publisher":"SciPost Foundation","status":"public","external_id":{"arxiv":["2504.03411"],"isi":["001593017800002"]},"file":[{"date_updated":"2025-11-24T08:42:42Z","date_created":"2025-11-24T08:42:42Z","relation":"main_file","file_name":"2025_SciPostPhys_Koutentakis.pdf","file_id":"20673","file_size":1725787,"content_type":"application/pdf","access_level":"open_access","creator":"dernst","success":1,"checksum":"04d0e47ba66c63737431d7b8ed1df4bc"}],"_id":"20666","date_published":"2025-10-01T00:00:00Z","corr_author":"1","arxiv":1,"intvolume":"        19","publication_identifier":{"eissn":["2542-4653"]},"publication_status":"published","tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"isi":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","year":"2025","citation":{"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,” <i>Scipost Physics</i>, vol. 19, no. 4. SciPost Foundation, 2025.","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.” <i>Scipost Physics</i>. SciPost Foundation, 2025. <a href=\"https://doi.org/10.21468/SciPostPhys.19.4.093\">https://doi.org/10.21468/SciPostPhys.19.4.093</a>.","ama":"Koutentakis G, Mistakidis SI, Grusdt F, Sadeghpour HR, Schmelcher P. Competition of light-and phonon-dressing in microwave-dressed Bose polarons. <i>Scipost Physics</i>. 2025;19(4). doi:<a href=\"https://doi.org/10.21468/SciPostPhys.19.4.093\">10.21468/SciPostPhys.19.4.093</a>","mla":"Koutentakis, Georgios, et al. “Competition of Light-and Phonon-Dressing in Microwave-Dressed Bose Polarons.” <i>Scipost Physics</i>, vol. 19, no. 4, 093, SciPost Foundation, 2025, doi:<a href=\"https://doi.org/10.21468/SciPostPhys.19.4.093\">10.21468/SciPostPhys.19.4.093</a>.","short":"G. Koutentakis, S.I. Mistakidis, F. Grusdt, H.R. Sadeghpour, P. Schmelcher, Scipost Physics 19 (2025).","apa":"Koutentakis, G., Mistakidis, S. I., Grusdt, F., Sadeghpour, H. R., &#38; Schmelcher, P. (2025). Competition of light-and phonon-dressing in microwave-dressed Bose polarons. <i>Scipost Physics</i>. SciPost Foundation. <a href=\"https://doi.org/10.21468/SciPostPhys.19.4.093\">https://doi.org/10.21468/SciPostPhys.19.4.093</a>","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."},"quality_controlled":"1","date_created":"2025-11-23T23:01:39Z","abstract":[{"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.","lang":"eng"}],"type":"journal_article","publication":"Scipost Physics","DOAJ_listed":"1","OA_place":"publisher","month":"10"},{"arxiv":1,"_id":"9769","date_published":"2021-07-13T00:00:00Z","external_id":{"isi":["000680039500013"],"arxiv":["2101.10958"]},"file":[{"checksum":"eaa847346b1a023d97bbb291779610ed","creator":"asandaue","content_type":"application/pdf","access_level":"open_access","success":1,"file_size":1085300,"file_name":"2021_SciPostPhysics_Brauneis.pdf","date_created":"2021-08-10T11:44:59Z","relation":"main_file","date_updated":"2021-08-10T11:44:59Z","file_id":"9875"}],"status":"public","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_processing_charge":"Yes","oa":1,"issue":"1","publisher":"SciPost Foundation","author":[{"last_name":"Brauneis","full_name":"Brauneis, Fabian","first_name":"Fabian"},{"first_name":"Hans-Werner","last_name":"Hammer","full_name":"Hammer, Hans-Werner"},{"orcid":"0000-0002-6990-7802","first_name":"Mikhail","id":"37CB05FA-F248-11E8-B48F-1D18A9856A87","last_name":"Lemeshko","full_name":"Lemeshko, Mikhail"},{"first_name":"Artem","orcid":"0000-0003-0393-5525","last_name":"Volosniev","full_name":"Volosniev, Artem","id":"37D278BC-F248-11E8-B48F-1D18A9856A87"}],"day":"13","ddc":["530"],"scopus_import":"1","doi":"10.21468/scipostphys.11.1.008","has_accepted_license":"1","department":[{"_id":"MiLe"}],"language":[{"iso":"eng"}],"article_type":"original","file_date_updated":"2021-08-10T11:44:59Z","oa_version":"Published Version","volume":11,"article_number":"008","ec_funded":1,"project":[{"name":"ISTplus - Postdoctoral Fellowships","grant_number":"754411","_id":"260C2330-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"},{"call_identifier":"H2020","name":"Angulon: physics and applications of a new quasiparticle","_id":"2688CF98-B435-11E9-9278-68D0E5697425","grant_number":"801770"}],"title":"Impurities in a one-dimensional Bose gas: The flow equation approach","date_updated":"2025-05-14T10:51:56Z","month":"07","publication":"SciPost Physics","type":"journal_article","quality_controlled":"1","year":"2021","citation":{"ieee":"F. Brauneis, H.-W. Hammer, M. Lemeshko, and A. Volosniev, “Impurities in a one-dimensional Bose gas: The flow equation approach,” <i>SciPost Physics</i>, vol. 11, no. 1. SciPost Foundation, 2021.","chicago":"Brauneis, Fabian, Hans-Werner Hammer, Mikhail Lemeshko, and Artem Volosniev. “Impurities in a One-Dimensional Bose Gas: The Flow Equation Approach.” <i>SciPost Physics</i>. SciPost Foundation, 2021. <a href=\"https://doi.org/10.21468/scipostphys.11.1.008\">https://doi.org/10.21468/scipostphys.11.1.008</a>.","ama":"Brauneis F, Hammer H-W, Lemeshko M, Volosniev A. Impurities in a one-dimensional Bose gas: The flow equation approach. <i>SciPost Physics</i>. 2021;11(1). doi:<a href=\"https://doi.org/10.21468/scipostphys.11.1.008\">10.21468/scipostphys.11.1.008</a>","mla":"Brauneis, Fabian, et al. “Impurities in a One-Dimensional Bose Gas: The Flow Equation Approach.” <i>SciPost Physics</i>, vol. 11, no. 1, 008, SciPost Foundation, 2021, doi:<a href=\"https://doi.org/10.21468/scipostphys.11.1.008\">10.21468/scipostphys.11.1.008</a>.","apa":"Brauneis, F., Hammer, H.-W., Lemeshko, M., &#38; Volosniev, A. (2021). Impurities in a one-dimensional Bose gas: The flow equation approach. <i>SciPost Physics</i>. SciPost Foundation. <a href=\"https://doi.org/10.21468/scipostphys.11.1.008\">https://doi.org/10.21468/scipostphys.11.1.008</a>","short":"F. Brauneis, H.-W. Hammer, M. Lemeshko, A. Volosniev, SciPost Physics 11 (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."},"date_created":"2021-08-04T15:00:55Z","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."}],"tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"isi":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publication_identifier":{"eissn":["2542-4653"]},"publication_status":"published","intvolume":"        11"}]