--- _id: '12154' abstract: - lang: eng text: We review our theoretical results of the sound propagation in two-dimensional (2D) systems of ultracold fermionic and bosonic atoms. In the superfluid phase, characterized by the spontaneous symmetry breaking of the U(1) symmetry, there is the coexistence of first and second sound. In the case of weakly-interacting repulsive bosons, we model the recent measurements of the sound velocities of 39K atoms in 2D obtained in the weakly-interacting regime and around the Berezinskii–Kosterlitz–Thouless (BKT) superfluid-to-normal transition temperature. In particular, we perform a quite accurate computation of the superfluid density and show that it is reasonably consistent with the experimental results. For superfluid attractive fermions, we calculate the first and second sound velocities across the whole BCS-BEC crossover. In the low-temperature regime, we reproduce the recent measurements of first-sound speed with 6Li atoms. We also predict that there is mixing between sound modes only in the finite-temperature BEC regime. acknowledgement: "This research is partially supported by University of Padova, BIRD grant “Ultracold atoms\r\nin curved geometries”. KF is supported by Fondazione CARIPARO with a PhD fellowship. AT is\r\npartially supported by French National Research Agency ANR Grant Droplets N. ANR-19-CE30-0003-02. LS thanks Herwig Ott and Sandro Wimberger for their kind invitation to the\r\nInternational Workshop “Quantum Transport with ultracold atoms” (2022)." article_number: '2182' article_processing_charge: Yes article_type: original author: - first_name: Luca full_name: Salasnich, Luca last_name: Salasnich - first_name: Alberto full_name: Cappellaro, Alberto id: 9d13b3cb-30a2-11eb-80dc-f772505e8660 last_name: Cappellaro orcid: 0000-0001-6110-2359 - first_name: Koichiro full_name: Furutani, Koichiro last_name: Furutani - first_name: Andrea full_name: Tononi, Andrea last_name: Tononi - first_name: Giacomo full_name: Bighin, Giacomo id: 4CA96FD4-F248-11E8-B48F-1D18A9856A87 last_name: Bighin orcid: 0000-0001-8823-9777 citation: ama: Salasnich L, Cappellaro A, Furutani K, Tononi A, Bighin G. First and second sound in two-dimensional bosonic and fermionic superfluids. Symmetry. 2022;14(10). doi:10.3390/sym14102182 apa: Salasnich, L., Cappellaro, A., Furutani, K., Tononi, A., & Bighin, G. (2022). First and second sound in two-dimensional bosonic and fermionic superfluids. Symmetry. MDPI. https://doi.org/10.3390/sym14102182 chicago: Salasnich, Luca, Alberto Cappellaro, Koichiro Furutani, Andrea Tononi, and Giacomo Bighin. “First and Second Sound in Two-Dimensional Bosonic and Fermionic Superfluids.” Symmetry. MDPI, 2022. https://doi.org/10.3390/sym14102182. ieee: L. Salasnich, A. Cappellaro, K. Furutani, A. Tononi, and G. Bighin, “First and second sound in two-dimensional bosonic and fermionic superfluids,” Symmetry, vol. 14, no. 10. MDPI, 2022. ista: Salasnich L, Cappellaro A, Furutani K, Tononi A, Bighin G. 2022. First and second sound in two-dimensional bosonic and fermionic superfluids. Symmetry. 14(10), 2182. mla: Salasnich, Luca, et al. “First and Second Sound in Two-Dimensional Bosonic and Fermionic Superfluids.” Symmetry, vol. 14, no. 10, 2182, MDPI, 2022, doi:10.3390/sym14102182. short: L. Salasnich, A. Cappellaro, K. Furutani, A. Tononi, G. Bighin, Symmetry 14 (2022). date_created: 2023-01-12T12:08:31Z date_published: 2022-10-17T00:00:00Z date_updated: 2023-08-09T10:13:17Z day: '17' ddc: - '530' department: - _id: MiLe doi: 10.3390/sym14102182 external_id: isi: - '000875039200001' file: - access_level: open_access checksum: 9b6bd0e484834dd76d7b26e3c5fba8bd content_type: application/pdf creator: dernst date_created: 2023-01-24T10:56:12Z date_updated: 2023-01-24T10:56:12Z file_id: '12361' file_name: 2022_Symmetry_Salsnich.pdf file_size: 843723 relation: main_file success: 1 file_date_updated: 2023-01-24T10:56:12Z has_accepted_license: '1' intvolume: ' 14' isi: 1 issue: '10' keyword: - Physics and Astronomy (miscellaneous) - General Mathematics - Chemistry (miscellaneous) - Computer Science (miscellaneous) language: - iso: eng month: '10' oa: 1 oa_version: Published Version publication: Symmetry publication_identifier: issn: - 2073-8994 publication_status: published publisher: MDPI quality_controlled: '1' scopus_import: '1' status: public title: First and second sound in two-dimensional bosonic and fermionic superfluids 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: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 14 year: '2022' ... --- _id: '10855' abstract: - lang: eng text: 'Consider a distributed task where the communication network is fixed but the local inputs given to the nodes of the distributed system may change over time. In this work, we explore the following question: if some of the local inputs change, can an existing solution be updated efficiently, in a dynamic and distributed manner? To address this question, we define the batch dynamic \congest model in which we are given a bandwidth-limited communication network and a dynamic edge labelling defines the problem input. The task is to maintain a solution to a graph problem on the labeled graph under batch changes. We investigate, when a batch of α edge label changes arrive, \beginitemize \item how much time as a function of α we need to update an existing solution, and \item how much information the nodes have to keep in local memory between batches in order to update the solution quickly. \enditemize Our work lays the foundations for the theory of input-dynamic distributed network algorithms. We give a general picture of the complexity landscape in this model, design both universal algorithms and algorithms for concrete problems, and present a general framework for lower bounds. In particular, we derive non-trivial upper bounds for two selected, contrasting problems: maintaining a minimum spanning tree and detecting cliques.' acknowledgement: "We thank Jukka Suomela for discussions. We also thank our shepherd Mohammad Hajiesmaili\r\nand the reviewers for their time and suggestions on how to improve the paper. This project\r\nhas received funding from the European Research Council (ERC) under the European Union’s\r\nHorizon 2020 research and innovation programme (grant agreement No 805223 ScaleML), from the European Union’s Horizon 2020 research and innovation programme under the Marie\r\nSk lodowska–Curie grant agreement No. 840605, from the Vienna Science and Technology Fund (WWTF) project WHATIF, ICT19-045, 2020-2024, and from the Austrian Science Fund (FWF) and netIDEE SCIENCE project P 33775-N." article_processing_charge: No article_type: original arxiv: 1 author: - first_name: Klaus-Tycho full_name: Foerster, Klaus-Tycho last_name: Foerster - first_name: Janne full_name: Korhonen, Janne id: C5402D42-15BC-11E9-A202-CA2BE6697425 last_name: Korhonen - first_name: Ami full_name: Paz, Ami last_name: Paz - first_name: Joel full_name: Rybicki, Joel id: 334EFD2E-F248-11E8-B48F-1D18A9856A87 last_name: Rybicki orcid: 0000-0002-6432-6646 - first_name: Stefan full_name: Schmid, Stefan last_name: Schmid citation: ama: Foerster K-T, Korhonen J, Paz A, Rybicki J, Schmid S. Input-dynamic distributed algorithms for communication networks. Proceedings of the ACM on Measurement and Analysis of Computing Systems. 2021;5(1):1-33. doi:10.1145/3447384 apa: Foerster, K.-T., Korhonen, J., Paz, A., Rybicki, J., & Schmid, S. (2021). Input-dynamic distributed algorithms for communication networks. Proceedings of the ACM on Measurement and Analysis of Computing Systems. Association for Computing Machinery. https://doi.org/10.1145/3447384 chicago: Foerster, Klaus-Tycho, Janne Korhonen, Ami Paz, Joel Rybicki, and Stefan Schmid. “Input-Dynamic Distributed Algorithms for Communication Networks.” Proceedings of the ACM on Measurement and Analysis of Computing Systems. Association for Computing Machinery, 2021. https://doi.org/10.1145/3447384. ieee: K.-T. Foerster, J. Korhonen, A. Paz, J. Rybicki, and S. Schmid, “Input-dynamic distributed algorithms for communication networks,” Proceedings of the ACM on Measurement and Analysis of Computing Systems, vol. 5, no. 1. Association for Computing Machinery, pp. 1–33, 2021. ista: Foerster K-T, Korhonen J, Paz A, Rybicki J, Schmid S. 2021. Input-dynamic distributed algorithms for communication networks. Proceedings of the ACM on Measurement and Analysis of Computing Systems. 5(1), 1–33. mla: Foerster, Klaus-Tycho, et al. “Input-Dynamic Distributed Algorithms for Communication Networks.” Proceedings of the ACM on Measurement and Analysis of Computing Systems, vol. 5, no. 1, Association for Computing Machinery, 2021, pp. 1–33, doi:10.1145/3447384. short: K.-T. Foerster, J. Korhonen, A. Paz, J. Rybicki, S. Schmid, Proceedings of the ACM on Measurement and Analysis of Computing Systems 5 (2021) 1–33. date_created: 2022-03-18T09:10:27Z date_published: 2021-03-01T00:00:00Z date_updated: 2023-09-26T10:40:55Z day: '01' department: - _id: DaAl doi: 10.1145/3447384 ec_funded: 1 external_id: arxiv: - '2005.07637' intvolume: ' 5' issue: '1' keyword: - Computer Networks and Communications - Hardware and Architecture - Safety - Risk - Reliability and Quality - Computer Science (miscellaneous) language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2005.07637 month: '03' oa: 1 oa_version: Preprint page: 1-33 project: - _id: 26A5D39A-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '840605' name: Coordination in constrained and natural distributed systems - _id: 268A44D6-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '805223' name: Elastic Coordination for Scalable Machine Learning publication: Proceedings of the ACM on Measurement and Analysis of Computing Systems publication_identifier: issn: - 2476-1249 publication_status: published publisher: Association for Computing Machinery quality_controlled: '1' related_material: record: - id: '10854' relation: shorter_version status: public scopus_import: '1' status: public title: Input-dynamic distributed algorithms for communication networks type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 5 year: '2021' ... --- _id: '11670' abstract: - lang: eng text: Auctions are widely used on the Web. Applications range from sponsored search to platforms such as eBay. In these and in many other applications the auctions in use are single-/multi-item auctions with unit demand. The main drawback of standard mechanisms for this type of auctions, such as VCG and GSP, is the limited expressiveness that they offer to the bidders. The General Auction Mechanism (GAM) of Aggarwal et al. [2009] takes a first step toward addressing the problem of limited expressiveness by computing a bidder optimal, envy-free outcome for linear utility functions with identical slopes and a single discontinuity per bidder-item pair. We show that in many practical situations this does not suffice to adequately model the preferences of the bidders, and we overcome this problem by presenting the first mechanism for piecewise linear utility functions with nonidentical slopes and multiple discontinuities. Our mechanism runs in polynomial time. Like GAM it is incentive compatible for inputs that fulfill a certain nondegeneracy assumption, but our requirement is more general than the requirement of GAM. For discontinuous utility functions that are nondegenerate as well as for continuous utility functions the outcome of our mechanism is a competitive equilibrium. We also show how our mechanism can be used to compute approximately bidder optimal, envy-free outcomes for a general class of continuous utility functions via piecewise linear approximation. Finally, we prove hardness results for even more expressive settings. acknowledgement: We would like to thank Veronika Loitzenbauer and the anonymous referees for their valuable feedback. article_number: '1' article_processing_charge: No article_type: original author: - first_name: Paul full_name: Dütting, Paul last_name: Dütting - first_name: Monika H full_name: Henzinger, Monika H id: 540c9bbd-f2de-11ec-812d-d04a5be85630 last_name: Henzinger orcid: 0000-0002-5008-6530 - first_name: Ingmar full_name: Weber, Ingmar last_name: Weber citation: ama: Dütting P, Henzinger MH, Weber I. An expressive mechanism for auctions on the web. ACM Transactions on Economics and Computation. 2015;4(1). doi:10.1145/2716312 apa: Dütting, P., Henzinger, M. H., & Weber, I. (2015). An expressive mechanism for auctions on the web. ACM Transactions on Economics and Computation. Association for Computing Machinery. https://doi.org/10.1145/2716312 chicago: Dütting, Paul, Monika H Henzinger, and Ingmar Weber. “An Expressive Mechanism for Auctions on the Web.” ACM Transactions on Economics and Computation. Association for Computing Machinery, 2015. https://doi.org/10.1145/2716312. ieee: P. Dütting, M. H. Henzinger, and I. Weber, “An expressive mechanism for auctions on the web,” ACM Transactions on Economics and Computation, vol. 4, no. 1. Association for Computing Machinery, 2015. ista: Dütting P, Henzinger MH, Weber I. 2015. An expressive mechanism for auctions on the web. ACM Transactions on Economics and Computation. 4(1), 1. mla: Dütting, Paul, et al. “An Expressive Mechanism for Auctions on the Web.” ACM Transactions on Economics and Computation, vol. 4, no. 1, 1, Association for Computing Machinery, 2015, doi:10.1145/2716312. short: P. Dütting, M.H. Henzinger, I. Weber, ACM Transactions on Economics and Computation 4 (2015). date_created: 2022-07-27T12:43:18Z date_published: 2015-12-02T00:00:00Z date_updated: 2023-02-09T10:08:41Z day: '02' doi: 10.1145/2716312 extern: '1' intvolume: ' 4' issue: '1' keyword: - Computational Mathematics - Marketing - Economics and Econometrics - Statistics and Probability - Computer Science (miscellaneous) language: - iso: eng month: '12' oa_version: None publication: ACM Transactions on Economics and Computation publication_identifier: eissn: - 2167-8383 issn: - 2167-8375 publication_status: published publisher: Association for Computing Machinery quality_controlled: '1' scopus_import: '1' status: public title: An expressive mechanism for auctions on the web type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 4 year: '2015' ... --- _id: '9145' abstract: - lang: eng text: "We have found a new way to express the solutions of the RSM (Reynolds Stress Model) equations that allows us to present the turbulent diffusivities for heat, salt and momentum in a way that is considerably simpler and thus easier to implement than in previous work. The RSM provides the dimensionless mixing efficiencies Γα (α stands for heat, salt and momentum). However, to compute the diffusivities, one needs additional information, specifically, the dissipation ε. Since a dynamic equation for the latter that includes the physical processes relevant to the ocean is still not available, one must resort to different sources of information outside the RSM to obtain a complete Mixing Scheme usable in OGCMs.\r\nAs for the RSM results, we show that the Γα’s are functions of both Ri and Rρ (Richardson number and density ratio representing double diffusion, DD); the Γα are different for heat, salt and momentum; in the case of heat, the traditional value Γh = 0.2 is valid only in the presence of strong shear (when DD is inoperative) while when shear subsides, NATRE data show that Γh can be three times as large, a result that we reproduce. The salt Γs is given in terms of Γh. The momentum Γm has thus far been guessed with different prescriptions while the RSM provides a well defined expression for Γm(Ri, Rρ). Having tested Γh, we then test the momentum Γm by showing that the turbulent Prandtl number Γm/Γh vs. Ri reproduces the available data quite well.\r\n\r\nAs for the dissipation ε, we use different representations, one for the mixed layer (ML), one for the thermocline and one for the ocean’s bottom. For the ML, we adopt a procedure analogous to the one successfully used in PB (planetary boundary layer) studies; for the thermocline, we employ an expression for the variable εN−2 from studies of the internal gravity waves spectra which includes a latitude dependence; for the ocean bottom, we adopt the enhanced bottom diffusivity expression used by previous authors but with a state of the art internal tidal energy formulation and replace the fixed Γα = 0.2 with the RSM result that brings into the problem the Ri, Rρ dependence of the Γα; the unresolved bottom drag, which has thus far been either ignored or modeled with heuristic relations, is modeled using a formalism we previously developed and tested in PBL studies.\r\nWe carried out several tests without an OGCM. Prandtl and flux Richardson numbers vs. Ri. The RSM model reproduces both types of data satisfactorily. DD and Mixing efficiency Γh(Ri, Rρ). The RSM model reproduces well the NATRE data. Bimodal ε-distribution. NATRE data show that ε(Ri < 1) ≈ 10ε(Ri > 1), which our model reproduces. Heat to salt flux ratio. In the Ri ≫ 1 regime, the RSM predictions reproduce the data satisfactorily. NATRE mass diffusivity. The z-profile of the mass diffusivity reproduces well the measurements at NATRE. The local form of the mixing scheme is algebraic with one cubic equation to solve." article_processing_charge: No article_type: original author: - first_name: V.M. full_name: Canuto, V.M. last_name: Canuto - first_name: A.M. full_name: Howard, A.M. last_name: Howard - first_name: Y. full_name: Cheng, Y. last_name: Cheng - first_name: Caroline J full_name: Muller, Caroline J id: f978ccb0-3f7f-11eb-b193-b0e2bd13182b last_name: Muller orcid: 0000-0001-5836-5350 - first_name: A. full_name: Leboissetier, A. last_name: Leboissetier - first_name: S.R. full_name: Jayne, S.R. last_name: Jayne citation: ama: 'Canuto VM, Howard AM, Cheng Y, Muller CJ, Leboissetier A, Jayne SR. Ocean turbulence, III: New GISS vertical mixing scheme. Ocean Modelling. 2010;34(3-4):70-91. doi:10.1016/j.ocemod.2010.04.006' apa: 'Canuto, V. M., Howard, A. M., Cheng, Y., Muller, C. J., Leboissetier, A., & Jayne, S. R. (2010). Ocean turbulence, III: New GISS vertical mixing scheme. Ocean Modelling. Elsevier. https://doi.org/10.1016/j.ocemod.2010.04.006' chicago: 'Canuto, V.M., A.M. Howard, Y. Cheng, Caroline J Muller, A. Leboissetier, and S.R. Jayne. “Ocean Turbulence, III: New GISS Vertical Mixing Scheme.” Ocean Modelling. Elsevier, 2010. https://doi.org/10.1016/j.ocemod.2010.04.006.' ieee: 'V. M. Canuto, A. M. Howard, Y. Cheng, C. J. Muller, A. Leboissetier, and S. R. Jayne, “Ocean turbulence, III: New GISS vertical mixing scheme,” Ocean Modelling, vol. 34, no. 3–4. Elsevier, pp. 70–91, 2010.' ista: 'Canuto VM, Howard AM, Cheng Y, Muller CJ, Leboissetier A, Jayne SR. 2010. Ocean turbulence, III: New GISS vertical mixing scheme. Ocean Modelling. 34(3–4), 70–91.' mla: 'Canuto, V. M., et al. “Ocean Turbulence, III: New GISS Vertical Mixing Scheme.” Ocean Modelling, vol. 34, no. 3–4, Elsevier, 2010, pp. 70–91, doi:10.1016/j.ocemod.2010.04.006.' short: V.M. Canuto, A.M. Howard, Y. Cheng, C.J. Muller, A. Leboissetier, S.R. Jayne, Ocean Modelling 34 (2010) 70–91. date_created: 2021-02-15T14:40:19Z date_published: 2010-05-12T00:00:00Z date_updated: 2022-01-24T13:51:35Z day: '12' doi: 10.1016/j.ocemod.2010.04.006 extern: '1' intvolume: ' 34' issue: 3-4 keyword: - Computer Science (miscellaneous) - Geotechnical Engineering and Engineering Geology - Atmospheric Science - Oceanography language: - iso: eng month: '05' oa_version: None page: 70-91 publication: Ocean Modelling publication_identifier: issn: - 1463-5003 publication_status: published publisher: Elsevier quality_controlled: '1' status: public title: 'Ocean turbulence, III: New GISS vertical mixing scheme' type: journal_article user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 volume: 34 year: '2010' ...