AAPPS BulletinPub Date : 2023-10-19DOI: 10.1007/s43673-023-00095-2
Matthew L. Kerr, Karen V. Kheruntsyan
{"title":"The theory of generalised hydrodynamics for the one-dimensional Bose gas","authors":"Matthew L. Kerr, Karen V. Kheruntsyan","doi":"10.1007/s43673-023-00095-2","DOIUrl":"10.1007/s43673-023-00095-2","url":null,"abstract":"<div><p>This article reviews the recent developments in the theory of generalised hydrodynamics (GHD) with emphasis on the repulsive one-dimensional Bose gas. We discuss the implications of GHD on the mechanisms of thermalisation in integrable quantum many-body systems as well as its ability to describe far-from-equilibrium behaviour of integrable and near-integrable systems in a variety of quantum quench scenarios. We outline the experimental tests of GHD in cold-atom gases and its benchmarks with other microscopic theoretical approaches. Finally, we offer some perspectives on the future direction of the development of GHD.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00095-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135666862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AAPPS BulletinPub Date : 2023-10-13DOI: 10.1007/s43673-023-00097-0
Xulong Wang, Wei Wang, Guancong Ma
{"title":"Extended topological mode in a one-dimensional non-Hermitian acoustic crystal","authors":"Xulong Wang, Wei Wang, Guancong Ma","doi":"10.1007/s43673-023-00097-0","DOIUrl":"10.1007/s43673-023-00097-0","url":null,"abstract":"<div><p>In Hermitian topological systems, topological modes (TMs) are bound to interfaces or defects of a lattice. Recent discoveries show that non-Hermitian effects can reshape the wavefunctions of the TMs and even turn them into extended modes occupying the entire bulk lattice. In this letter, we experimentally demonstrate such an extended TM (ETM) in a one-dimensional (1D) non-Hermitian acoustic topological crystal. The acoustic crystal is formed by a series of coupled acoustic resonant cavities, and the non-Hermiticity is introduced as a non-reciprocal coupling coefficient using active electroacoustic controllers (AECs). Our work highlights the potential universality of ETMs in different physical systems and resolves the technical challenges in the further study of ETMs in acoustic waves.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00097-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135805438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AAPPS BulletinPub Date : 2023-10-04DOI: 10.1007/s43673-023-00089-0
Jianning Li, Haodi Liu, Zhihai Wang, X. X. Yi
{"title":"Enhanced parameter estimation by measurement of non-Hermitian operators","authors":"Jianning Li, Haodi Liu, Zhihai Wang, X. X. Yi","doi":"10.1007/s43673-023-00089-0","DOIUrl":"10.1007/s43673-023-00089-0","url":null,"abstract":"<div><p>Quantum metrology aims at delivering new quantum-mechanical improvement to technologies of parameter estimations with precision bounded by the quantum Cramér-Rao bound. The currently used quantum Cramér-Rao bound was established with measurements of observables restricted to be Hermitian. This constrains the bound and limits the precision of parameter estimation. In this paper, we lift the constraint and derive a previously unknown quantum Cramér-Rao bound. We find that the new bound can reach arbitrary small value with mixed states and it breaks the Heisenberg limit in some cases. We construct a setup to measure non-Hermitian operators and discuss the saturation of the present bound. Two examples—the phase estimation with Greenberger-Horne-Zeilinger states of trapped ions and the adiabatic quantum parameter estimation with the nuclear magnetic resonance—are employed to demonstrate the theory. The present study might open a new research direction—non-Hermitian quantum metrology.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00089-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135591811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AAPPS BulletinPub Date : 2023-10-02DOI: 10.1007/s43673-023-00093-4
Chenyang Jiang
{"title":"An overview of polarized neutron instruments and techniques in Asia Pacific","authors":"Chenyang Jiang","doi":"10.1007/s43673-023-00093-4","DOIUrl":"10.1007/s43673-023-00093-4","url":null,"abstract":"<div><p>Polarized neutron scattering is an indispensable tool for exploring a vast range of scientific phenomena. With its dynamic scientific community and significant governmental support as well as the rapid economic growth, the Asia–Pacific region has become a key player in the worldwide neutron scattering arena. From traditional research reactors to cutting-edge spallation neutron sources, this region is home to a myriad of advanced instruments offering a wide range of polarized neutron capabilities. This review aims to provide a comprehensive overview of the development and current status of polarized neutron instruments and techniques in the Asia–Pacific region, emphasizing the important role of the Asia–Pacific region in shaping the landscape of global polarized neutron scattering development.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00093-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135830223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AAPPS BulletinPub Date : 2023-09-26DOI: 10.1007/s43673-023-00092-5
Jia Wang
{"title":"Functional determinant approach investigations of heavy impurity physics","authors":"Jia Wang","doi":"10.1007/s43673-023-00092-5","DOIUrl":"10.1007/s43673-023-00092-5","url":null,"abstract":"<div><p>In this brief review, we report some new development in the functional determinant approach (FDA), an exact numerical method, in the studies of a heavy quantum impurity immersed in Fermi gases and manipulated with radio-frequency pulses. FDA has been successfully applied to investigate the universal dynamical responses of a heavy impurity in an ultracold ideal Fermi gas in both the time and frequency domain, which allows the exploration of the renowned Anderson’s orthogonality catastrophe (OC). In such a system, OC is induced by the multiple particle-hole excitations of the Fermi sea, which is beyond a simple perturbation picture and manifests itself as the absence of quasiparticles named polarons. More recently, two new directions for studying heavy impurity with FDA have been developed. One is to extend FDA to a strongly correlated background superfluid background, a Bardeen–Cooper–Schrieffer (BCS) superfluid. In this system, Anderson’s orthogonality catastrophe is prohibited due to the suppression of multiple particle-hole excitations by the superfluid gap, which leads to the existence of genuine polaron. The other direction is to generalize the FDA to the case of multiple RF pulses scheme, which extends the well-established 1D Ramsey spectroscopy in ultracold atoms into multidimensional, in the same spirit as the well-known multidimensional nuclear magnetic resonance and optical multidimensional coherent spectroscopy. Multidimensional Ramsey spectroscopy allows us to investigate correlations between spectral peaks of an impurity-medium system that is not accessible in the conventional one-dimensional spectrum.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00092-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134960045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AAPPS BulletinPub Date : 2023-09-19DOI: 10.1007/s43673-023-00087-2
Koichiro Furutani, Luca Salasnich
{"title":"Fokker-Planck equations for a trapped particle in a quantum-thermal Ohmic bath: general theory and applications to Josephson junctions","authors":"Koichiro Furutani, Luca Salasnich","doi":"10.1007/s43673-023-00087-2","DOIUrl":"10.1007/s43673-023-00087-2","url":null,"abstract":"<div><p>We consider a particle trapped by a generic external potential and under the influence of a quantum-thermal Ohmic bath. Starting from the Langevin equation, we derive the corresponding Schwinger-Keldysh action. Then, within the path-integral formalism, we obtain both the semiclassical Fokker-Planck equation and the quantum Fokker-Planck equation for this out-of-equilibrium system. In the case of an external harmonic potential and in the underdamped regime, we find that our Fokker-Planck equations contain an effective temperature <span>(T_{text {eff}})</span>, which crucially depends on the interplay between quantum and thermal fluctuations in contrast to the classical Fokker-Planck equation. In the regime of high temperatures, one recovers the classical Fokker-Planck equation. As an application of our result, we also provide the stationary solution of the semiclassical Fokker-Planck equations for a superconducting Josephson circuit and for a Bose Josephson junction, which are experimentally accessible.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00087-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135014724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AAPPS BulletinPub Date : 2023-09-13DOI: 10.1007/s43673-023-00090-7
Shou-hua Zhu
{"title":"CDF W mass anomaly revisited","authors":"Shou-hua Zhu","doi":"10.1007/s43673-023-00090-7","DOIUrl":"10.1007/s43673-023-00090-7","url":null,"abstract":"<div><p>The CDF, ATLAS, and LHCb have released the measurements on the W boson mass <span>(m_W)</span> at <span>(sqrt{S}=1.96, 7, 13 TeV)</span>, respectively. The measured values show the declining tendency, namely <span>(m_W)</span> decreases with the increment of the collider energy. If the declining tendency is confirmed, it might be the signal of metric field at high-energy colliders. In this paper, we propose a model to account for such tendency and explore the properties of the model.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00090-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135741106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AAPPS BulletinPub Date : 2023-07-31DOI: 10.1007/s43673-023-00086-3
Min-Di Zheng, Feng-Zhi Chen, Hong-Hao Zhang
{"title":"The (Well nu)-vertex corrections to W-boson mass in the R-parity violating MSSM","authors":"Min-Di Zheng, Feng-Zhi Chen, Hong-Hao Zhang","doi":"10.1007/s43673-023-00086-3","DOIUrl":"10.1007/s43673-023-00086-3","url":null,"abstract":"<div><p>Inspired by the astonishing <span>(7sigma)</span> discrepancy between the recent CDF-II measurement and the standard model prediction on the mass of <i>W</i>-boson, we investigate the <span>(lambda ')</span>-corrections to the vertex of <span>(mu rightarrow nu _mu ebar{nu _e})</span> decay in the context of the <i>R</i>-parity violating minimal supersymmetric standard model. These corrections can raise the <i>W</i>-boson mass independently. Combined with recent <i>Z</i>-pole and kaon decay measurements, <span>(m_W lesssim 80.37)</span> GeV can be reached. We find that these vertex corrections cannot explain the CDF result entirely at the <span>(2sigma)</span> and even <span>(3sigma)</span> levels. However, these corrections together with the oblique contributions can be accordant with the CDF-II result and relevant bounds at the <span>(3sigma)</span> level.</p></div>","PeriodicalId":100007,"journal":{"name":"AAPPS Bulletin","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s43673-023-00086-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89032741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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