可積量子系統、強耦合電-聲系統 、引力波與中微子質量 | 本週物理講座

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報告人：郭領陣，天津大學

時間：6月18日（週二）11:00

單位：中國科學院理論物理研究所

地點：南樓6620

摘要：

Bosonic codes use nonclassical bosonic states to encode and process quantum information, which renders them hardware-efficient compared to codes with two-level systems. However,  it is still a challenging task to prepare high-quality bosonic code states with high efficiency. In our recent work [Phys. Rev. Lett. 132 , 023602 (2024)], we developed a noncommutative Fourier transformation technique and the new method to generate arbitrary Hamiltonian in the Floquet phase space of a periodically driven oscillator. We establish the relationship between an arbitrary target Floquet Hamiltonian in phase space and the periodic driving potential in real space. Our protocol can be realized in a range of experimental platforms for nonclassical state generation and bosonic quantum computation.

報告人簡介：

Dr. Lingzhen Guo is currently an Associate Professor at the Center for Joint Quantum Studies, Tianjin University. He finished his undergraduate and graduate studies at the Beijing Normal University. From 2010.09 to 2012.08, he worked as a joint PhD student at the Karlsruhe Institute of Technology (KIT), Germany. From 2013.08 to 2023.12, he worked as postdoc at KIT, Chalmers University of Technology (Sweden) and Max Planck Institute for the Science of Light (MPL) in Erlangen (Germany). He joined Tianjin University as an Associate Professor from April of 2023.

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報告人：馬儒軍，南開大學

時間：6月18日（週二）16:00

單位：中國科學院物理研究所

地點：M253會議室

摘要：

低能耗熱管理技術既是未來高新技術發展的重要保障又符合我國“雙碳”的戰略目標。然而，傳統的熱管理系統通常耗電量大、不環保、體積大等。這裡，爲了降低能耗，我們開展了節能高效固態熱管理系統研究，從低能耗的電卡效應到零能耗的輻射效應的熱管理系統，再到自持續的可穿戴固態熱管理系統。利用電卡效應制備的低能耗熱管理系統，不僅具備環保、高效、小型化且結構簡單，還可以對電子器件進行時空精準控溫。利用輻射效應制備的零能耗熱管理系統，不僅解決了傳統輻射熱管理系統在應對動態溫度變化時的侷限性，更實現了保溫與製冷雙模式的零能耗切換效果，顯著提升了熱管理系統的能效和靈活性。另外，通過光伏模塊與電卡-靜電力模塊集成的自持續全天候可穿戴熱管理衣物，從根本上解決了電卡效應熱管理系統的供能難題，可根據人體制冷/加熱需求實現了快速體溫調節，並擴大了人體熱舒適區範圍。這種節能的固態熱管理系統爲我國“雙碳”目標的順利實現提供了理論和技術支撐。

報告人簡介：

馬儒軍，南開大學材料科學與工程學院教授、博導，國家四青人才，科技部國家重點研發計劃“變革性技術”重點專項課題負責人，主持國家自然科學基金面上項目（2）與國際交流項目、天津市自然科學基金重點項目等。2013年2月博士畢業於韓國成均館大學納米科技學院（導師：Seunghyun Baik教授），隨後在該校能源科學學院與基礎科學研究院從事博士後研究員的工作，並於2015年4月加入美國加州大學洛杉磯分校（UCLA）裴啓兵教授課題組繼續從事博士後研究員的工作。2018年9月加入南開大學材料科學與工程學院。

主要研究方向爲柔性主動/被動固態製冷材料與器件及多功能柔性熱電材料與器件。近年來以通訊或第一作者發表的國際著名期刊有Science (2), PNAS, Nature Communications, Joule (2), Chemical Society Reviews, Energy & Environmental Science, Advanced Materials (4), Advanced Energy Materials (2), Nano Letters (7), ACS nano (2)等；授權美國、中國、韓國專利10餘項，申請國際專利2項。

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報告人：Peiran Li，University of Minnesota

時間：6月19日（週三）10:00

單位：北京大學物理學院

地點：物理學院西B105

摘要：

Electroweak physics has been tested and exploitedat current LHC very comprehensively. It seems to be in an auto-piloting mode that our job becomes either searching BSM physics or improving the precision of SM measurement. Our recent work proposes a new channel, W boson 4-lepton decay, which people have not paid enough attention, but the current LHC is able to measure. Furthermore, this channel can be used to constrain other BSM model, such as L_\mu-L_\tau. In the latter half of my talk, I would like to switch to the SM precision measurement at future 10 TeV muon collider. Especially, I will discuss the Higgs total width measurement via vector bosonfusion at muon collider and the global constraints on Higgs effective couplings, showing the sensitivity of future muon collider.

報告人簡介：

Peiran Li is currently a graduate student at University of Minnesota starting in 2021. He obtained his bachelor's degreeat Stony Brook University in 2019 and worked as research assistant at IHEP during 2020. He mainly works on particle physics, SM/BSM phenomenology, collider physics.

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報告人：Tong (Arthur) Wu，University of Pittsburgh

時間：6月19日（週三）11:00

單位：北京大學物理學院

地點：物理學院西B105

摘要：

In this talk I will first introduce how to calculate the effective potential and gravitation wave from phase transition, the traditional method and the dimensional reduction method wil be discussed and compared. Then l will present the gravitational wave signal generated from neutrino inverse seesaw model and show the complementarity to the collider search for heavy neutral lepton.

報告人簡介：

Tong (Arthur) Wu is a graduate student at the University of Pittsburgh starting in 2022, after obtained his bachelor's degree at University of Science and Technology of China.

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報告人：Dr. Zechuan Zheng，PI

時間：6月19日（週三）15:00

單位：北京大學物理學院

地點：物理學院西B105

摘要：

This presentation focuses on the lattice and matrix bootstrap methods, distinguished by their utilization of the equation of motion as bootstrap constraints. These methods share key characteristics with the closely related fields of quantum mechanics bootstrap and many-body bootstrap. The presentation will cover the application of the bootstrap method to the matrix model theory, with a particular emphasis on the ground state of BFSS. Additionally, l will discuss the latest results in bootstrap finite N matrix model theory, including the recent bootstrap result of SU(2) lattice gauge theory.

報告人簡介：

Dr. Zechuan Zheng is presently serving as a postdoctoral fellow at the Perimeter Institute of Theoretical Physics. He obtained his Bachelor's degree from Peking University in 2016 and completed his Ph.D. in theoretical physics at École Normale Supérieure, Paris, France,in 2023. His areas of research encompass applying the bootstrap method to different areas of theoretical physics.

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報告人：Dr. Zhaoyu Han，Harvard University

時間：6月20日（週四）10:00

單位：中國科學院物理研究所

騰訊會議ID：838-194-182

會議密碼：0620

摘要：

Resonating valence bond (RVB) states describe one of the most extreme classes of quantum phases that feature emergent gauge fields at low energy. Since this concept was revived by Anderson in 1973 in the spin physics context, the pursuits of such phases have been mostly restricted to frustrated antiferromagnets. In this talk, I will introduce an entirely different route to the possible realization of such phases, which builds on phonon degrees of freedom on lattice bonds – roughly realizing the original intuitive depiction of RVB by Pauling in 1949. I will provide (at least) two explicit minimal models as caricatures of certain types of electron-phonon couplings, where it can be shown with asymptotically exact arguments that deconfined gauge fields emerge in certain strong coupling regimes of their phase diagrams. Particularly I will show that such phases can appear in electronically trivial 'band insulators' proximate to ferroelectric ordering.

報告人簡介：

Zhaoyu Han is a postdoctoral fellow in condensed matter theory at Harvard University. He earned his PhD from Stanford University in 2024 and BS from Peking University in 2018. His current research interests span strongly coupled electron-phonon systems, topological phases and transitions, and flat band materials.

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報告人：Andreas Klümper，Wuppertal University

時間：6月20日（週四）10:00

單位：中國科學院物理研究所

報告地點：M830

摘要：

This talk explores the intriguing physical properties of integrable low-dimensional models, specifically focusing on 1D quantum systems and 2D classical systems such as the spin-1/2 Heisenberg chain and the 1D Hubbard model. The classical six-vertex model on the square lattice and its generalizations also play a crucial role in understanding these prototypes.

The first part of the talk elucidates the connection between 2D classical models and 1D quantum systems. By exploring the Yang-Baxter equation for local Boltzmann weights, we unveil a family of commuting transfer matrices. These matrices operate in the Hilbert space of the 1D quantum system, ultimately leading to a lattice path integral formulation of the Heisenberg and Hubbard Hamiltonians at arbitrary temperatures. The practical implications include a compact representation of thermodynamic quantities based on a finite set of non-linear integral equations, a departure from the traditional TBA approach involving infinitely many equations.

Transitioning to the second part, we delve into seminal results in integrable systems and touch upon current research topics, such as thermal and spin transport in the Heisenberg chain. A special focus is placed on the staggered Heisenberg spin chain, where we present results on the finite-size spectrum for varying sizes, ranging from $L = 10$ to $L = 10^{24}$.

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報告人：David Wu，Harvard University

時間：6月20日（週四）15:00

單位：北京大學物理學院

地點：物理學院西B105

摘要：

Quantum gravity has a natural cutoff given by the Planck scale. However, the EFT of quantum gravity can break down at a lower scale known as the species scale, which is when higher-curvature corrections become important. Additionally, there is a third scale which marks the inverse length (or the temperature) of the smallest black hole where the EFT gives a correct description of its entropy and free energy. Understanding the distinction and interplay among these three scales can shed light on fundamental aspects of quantum gravity and have important applications to phenomenology. In this talk, l will introduce the species scale as a moduli-dependent quantity in supersymmetric theories and motivate the existence of the black hole scale in quantum gravity. At last, I will provide evidence for two global bounds of the species scale and the black hole scale over the moduli space of quantum gravity.

報告人簡介：

David Wu completed his undergraduate studies at Caltech and is currently a third year PhD student in the Center of Fundamental Laws in the department of physics at Harvard University under the supervision of Prof, Cumrun Vafa. He is mostly interested in the swampland program of quantum gravity.

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報告人：Gwenael Giacinti，賈鴻宇，上海交通大學

時間：6月20日（週四）15:30

單位：北京大學物理學院

地點：KIAA-Auditorium

摘要：

AGN jets are some of the few astrophysical environments able to confine ultra-high-energy cosmic rays, but whether they are capable of accelerating these particles is unknown. In this work, we revisit particle acceleration at relativistic magnetized shocks beyond the local uniform field approximation, by considering the global transverse structure of the jet. Using large two-dimensional particle-in-cell simulations of a relativistic electron-ion plasma jet, we show that the termination shock forming at the interface with the ambient medium accelerates particles up to the confinement limit. The radial structure of the jet magnetic field leads to a relativistic velocity shear that excites a von Kármán vortex street in the downstream medium trailing behind an over-pressured bubble filled with cosmic rays. Particles are efficiently accelerated at each crossing of the shear flow boundary layers. These findings support the idea that extragalactic plasma jets may be capable of producing ultra-high-energy cosmic rays. This extreme particle acceleration mechanism may also apply to microquasar jets.

報告人簡介：

Gwenael Giacinti is a T. D. Lee Fellow at the Tsung-Dao Lee Institute, and a Tenure-track Associate Professor at Shanghai Jiao Tong University. Prior to that, he held postdoctoral researcher positions at the University of Oxford (United Kingdom) and at the Max Planck Institute for Nuclear Physics in Heidelberg (Germany), and earned his Ph.D. degree from Paris 7 University (France). He is interested in a number of topics in theoretical high-energy astrophysics and particle astrophysics, including cosmic-ray propagation, particle acceleration in pulsar wind nebulae, supernovae and supernova remnants, as well as gamma-ray astronomy. He is also interested in related plasma astrophysics problems, such as shock physics in the context of supernova shock breakout. He is the science working group coordinator of the Southern Wide field-of-view Gamma-ray Observatory (SWGO), and a member of the LHAASO Collaboration.

圖片來源於：https://neutrino-science.com/a-new-gravitational-wave-collection-contains-black-holes-of-all-shapes-and-sizes/

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