1

報告人：Katsuya Hashino，F(xiàn)ukushima College

時間：3月11日（周二）10:30

單位：北京大學(xué)物理學(xué)院

地點(diǎn)：物理學(xué)院西樓B105

摘要：

In the Higgs potential of the standard model, it is known that the electroweak phase transition in the early universe is a crossover. However, the phase transition can occur as first-order when new physics effects contribute to the potential. lf the first-order phase transition took place in the early universe, the graitational waves are produced by bubble collision. Since theenergy of gravitational waves depend on the shape of the potential，it may be possible to explore the new physics effects in the potential through their observations. However, the spectrum of gravitational wave from first-order phase transition has some theoretical uncertainties. In this talk, we focus on some models beyond the standard model as an example, and discuss testaibility of them through the obseration of graitational wave. We take into account theoretical uncertainties, particularly those arising from renormalization group running effects, in the GW spectrum and discuss how precisely new physics effects can be probed.

報告人簡介：

Katsuya Hashino received his Ph. D from University of Toyama in 2019, and is now an assistant professor at Fukushima College. He has worked at Osaka University, Peking University and Tokyo University of Science as a postdoc. His main interest is Higgs physics. Especially, he has focused on the dynamics of electroweak phase transitions in the eary Universe.

2

報告人：劉景鋮，南京大學(xué)計算機(jī)學(xué)院

時間：3月11日（周二）12：00

單位：江蘇省物理學(xué)會

鏈接：

摘要：

給定一個復(fù)雜系統(tǒng)的部分觀察，如何高效地按照符合給定觀察的條件分布進(jìn)行模擬/采樣？這樣的計算采樣問題在現(xiàn)代數(shù)據(jù)分析和機(jī)器學(xué)習(xí)中扮演著非常重要的角色，也有著理論物理學(xué)的背景。事實上，計算機(jī)科學(xué)中經(jīng)典的約束求解問題，均對應(yīng)著一個帶復(fù)雜多體相互作用的粒子系統(tǒng)。因此計算機(jī)科學(xué)關(guān)心的約束求解問題中，解空間的整體幾何性質(zhì)的變化，也對應(yīng)于物理系統(tǒng)中的相變現(xiàn)象。對于這些相變現(xiàn)象和采樣算法的深入理論研究，不僅僅有助于回答“計算問題何時是困難的，何時是容易的”這樣的基礎(chǔ)科學(xué)問題，也在實踐應(yīng)用中證明了其價值。本報告將簡單介紹這一研究方向，和一些我們已知的結(jié)果。

報告人簡介：

劉景鋮，南京大學(xué)計算機(jī)學(xué)院副教授，2019博士畢業(yè)于加州大學(xué)伯克利分校，導(dǎo)師是哥德爾獎得主Alistair Sinclair；畢業(yè)后在加州理工學(xué)院的計算與數(shù)學(xué)科學(xué)學(xué)院擔(dān)任Wally Baer and Jeri Weiss講席博士后。主要研究方向包括隨機(jī)算法，計數(shù)與采樣問題，計算相變理論和理論計算機(jī)科學(xué)，代表成果全部發(fā)表在STOC, FOCS, SODA和Journal of the ACM, SIAM Journal on Computing等國際一流的會議與期刊上；成果中兩項分別入選差分隱私教材Hands-On Differential Privacy，和圖靈獎得主Avi Wigderson編寫的科普書籍《數(shù)學(xué)與計算》。入選國家青年高層次人才，主持國家自然科學(xué)基金面上項目。

3

報告人：Zhewei Yin，Northwestern University&Argonne National Laboratory

時間：3月11日（周二）14：00

單位：北京大學(xué)物理學(xué)院

地點(diǎn)：物理學(xué)院西樓B105

摘要：

The scattering amplitudes program aims to obtain observables from quantum field theory without cumbersome local formulations such as Feynman diagrams. A key step in this procedure is to determine the constraints satisfied by the on-shell amplitudes, according to the guiding principles of the theory in consideration. Recently a novel group of constraints originated from concepts in quantum information science has been increasingly drawing people's attention. I will first discuss the investigation on the amount of entanglement resulted in particle scattering, and reveal a universal correspondence between entanglement entropy and (semi)-inclusive cross sections. A careful formulation of wave packets for the initial states is essential in arriving at this relation. I will then discuss in the context of particle scattering the notion of magic, which quantifies the computational advantage of quantum states over classical algorithms. Research on this topic is still in its early stage, and can benefit both fundamental physics and quantum information science.

報告人簡介：

Dr Zhewei Yin obtained his BSc degree in 2015 at Peking University, China, and his PhD degree in 2020 at Northwestern University, USA. He then became a postdoctoral researcher at Uppsala University, Sweden, after which he has been holding a joint appointment as a postdoctoral fellow at Northwestern University and Argonne National Laboratory, USA. He works in the field of theoretical high energy physics, with a focus on discovering new properties and developing modern methods in scattering amplitudes and effective field theories, as well as connecting these formal development to particle phenomenology, gravitational wave physics and quantum information science.

4

報告人：Hiroshi Shinaoka，Saitama University

時間：3月12日（周三）11:00

單位：中國科學(xué)院理論物理所

地點(diǎn)：北樓322

摘要：

Recently, quantics tensor trains (QTT) have been proposed as an efficient numerical tool for quantum field calculations. QTT can handle the coexistence of widely varying length, energy, and time scales while enabling fundamental operations such as Fourier transforms and convolutions in a compressed form.

In this seminar, I will give a blackboard-style talk on recent efforts to solve quantum field problems in the imaginary-time formalism, including the solution of parquet equations and multiorbital impurity models. For those unfamiliar with QTT, I will provide a brief introduction.

報告人簡介：

Hiroshi Shinaoka is a computational physicist with a broad research scope, spanning from first-principles calculations of strongly correlated materials to the development and application of tensor network methods. Currently an Associate Professor at Saitama University, with a diverse academic background including international research experience at ETH Zurich. Actively involved in the development of open-source software and making significant contributions to computational physics and quantum material science.

5

報告人：Chenjie Wang，University of Hong Kong

時間：3月12日（周三）15:00

單位：北京大學(xué)物理學(xué)院

地點(diǎn)：物理樓，西563會議室

摘要：

I will discuss a construction of a family of 1D quantum lattice models that respect unitary fusion category symmetry. This family can be thought of as edge models of 2D symmetry-enriched topological states. An interesting feature of these models is that they often (but may not always) exhibit a gapless critical phase, i.e., a gapless region of codimension zero in the parameter space, due to the presence of fusion category symmetry. I will discuss numerical results of some examples.

報告人簡介：

Chenjie Wang, Associate Professor at University of Hong Kong, graduated from University of Science and Technology of China in 2007 and obtained his PhD from Brown University in 2012. He has been working on transport in quantum Hall effects and theory of strongly correlated topological phases. His recent research interests include localization phenomenon and generalized symmetries in topological phases and quantum criticality.

6

報告人：Prof. Francisco J. Garcia-Vidal, Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Spain

時間：3月13日（周四）14:30

單位：北京大學(xué)物理學(xué)院

地點(diǎn)：物理學(xué)院中215會議室

摘要：

When the interaction between light and matter is strong enough, photon and matter excitations mix to create hybrid light/matter states called polaritons. Traditionally, their hybrid character has been used to achieve new functionalities in which polaritons are utilized as dressed photons. However, over the last ten years, it has become clear that the strong light-matter coupling regime can be used with an alternative purpose: to significantly modify material properties by dressing the matter excitations. Under strong coupling conditions, it has been shown that energy transport and harvesting in organic materials can be enhanced and that the energy landscape of the molecules can be altered in such a way that photochemical reactions and even ground-state chemical reactions can be modified. This new platform for creating quantum materials has triggered the search for achieving strong light-matter coupling conditions with other types of electronic excitations, such as those associated with excitons in van der Waals 2D materials and perovskite quantum dot solids, among others.

In this seminar I will present the main findings in this brand-new research field, but also our accompanying efforts in the last ten years to developing an accurate theoretical formalism, able to capture the complex and quantum nature of the electromagnetic fields associated with the nanophotonic structures in which polaritons emerge.

報告人簡介：

Francisco J. Garcia-Vidal is a scientific group leader and full professor at the Physics department of the Autonomous University of Madrid (UAM) in Spain. Prof. Garcia-Vidal and his group have worked in different areas within Plasmonics and Metamaterials such as: surface enhanced Raman scattering, the phenomenon of extraordinary transmission of light and other waves through subwavelength apertures, the development of the concept of spoof surface plasmons and, more recently, Quantum Nanophotonics. Prof. Garcia-Vidal has authored around 300 refereed journal articles, which have received more than 48,000 citations (H-index: 103), and he has been included seven times in the list of Highly Cited Researchers in the field of Physics. He is also the founding director of the Condensed Matter Physics Center (IFIMAC) at UAM, and he was also the recipient of an ERC Advanced Grant (2012-2017) devoted to analysing quantum effects in Plasmonics. Prof. Garcia-Vidal is also a Fellow of the Optical Society of America and, from January 2018 to December 2021, served as a Divisional Associate Editor of Physical Review Letters. He was the recipient of the King Jaume I prize for Basic Research in year 2020, and he has been also awarded with the National prize of Physics in Spain in year 2021.

7

報告人：Nora Brambilla，慕尼黑工業(yè)大學(xué)

時間：3月13日（周四）15:00

單位：北京大學(xué)物理學(xué)院

鏈接：

摘要：

In this colloquium, we delve into the construction of a potential NREFT (pNREFT), a framework that directly tackles bound state dynamics reimagining quantum mechanics from field theory. Focusing on heavy quarkonia, pNRQCD facilitates systematic definitions and precise calculations for high-energy collider observables.

At the cutting edge, we investigate nonrelativistic bound states in intricate environments, like the newly discovered exotics X, Y, Z above the strong decay threshold and the behavior in out-of-equilibrium scenarios, such as quarkonium suppression in a Quark Gluon Plasma or dark matter interactions in the early universe. Our ability to achieve precision calculations and control strongly interacting systems is closely linked to bridging perturbative methods with nonperturbative tools, notably numerical lattice gauge theories.

報告人簡介：

Nora Brambilla是粒子物理與核物理領(lǐng)域國際頂級專家學(xué)者。她的研究興趣在于理論粒子與核物理；強(qiáng)相互作用物質(zhì)；用于標(biāo)準(zhǔn)模型的有效場論、有限溫度量子色動力學(xué)、夸克膠子等離子體、非平衡態(tài)物理學(xué)、格點(diǎn)量子色動力學(xué)以及非微擾技術(shù)。她的成名作是提出了pNREFT（勢非相對論有效場論）理論，建立了用量子場論系統(tǒng)精確描述量子力學(xué)問題的橋梁。

2023 年獲得歐洲研究理事會高級資助項目，項目名稱為 “EFT-XYZ：利用有效場論理解并預(yù)測 XYZ 奇異強(qiáng)子的性質(zhì)”。2012 年當(dāng)選為美國物理學(xué)會會士，表彰其在重夸克-反夸克系統(tǒng)理論方面的貢獻(xiàn)，包括新有效場論的發(fā)展，以及通過創(chuàng)立并領(lǐng)導(dǎo)夸克偶素工作組對夸克偶素物理學(xué)領(lǐng)域所做出的貢獻(xiàn)。她創(chuàng)立了國際夸克偶素工作組（QWG，2002 年成立）和夸克禁閉系列會議（1994開始）。

8

報告人：Lixin Dai，香港大學(xué)

時間：3月13日（周四）15:30

單位：北京大學(xué)物理學(xué)院

地點(diǎn)：KIAA-auditorium

摘要：

Tidal disruption events (TDEs) are among the most fascinating astronomical phenomena, offering a unique probe into the properties of massive black holes and the nuclear environments of galaxies. In this talk, I will present results from theoretical calculations of the realistic rates of TDEs for both supermassive and intermediate-mass black holes. These results reveal how TDE rates depend on black hole mass, stellar dynamics, and galactic environments. I will also show state-of-the-art simulations of TDE accretion, outflows and emissions, demonstrating how these processes produce the diverse emission features we observe, including Bowen fluorescence lines. Finally, I will discuss the broader implications of TDEs for black hole growth, particularly in the early universe, and their role in shaping galactic evolution. By exploring these results, we can better understand the physics of TDEs and their critical role in the growth of black holes and the evolution of galaxies across cosmic time.

報告人簡介：

Lixin Dai is an associate professor in the Department of Physics of the University of Hong Kong. Prof. Dai received her B.S. in Physics and Mathematics from the Hong Kong University of Science and Technology and her M.S. and Ph.D. in Physics from Stanford University. She was a joint postdoc fellow at the Yale University and University of Chile, and then a research associate at the University of Maryland. She joined the University of Copenhagen as an assistant professor before joining the University of Hong Kong. Her research interests are mainly in theoretical and computational high-energy and time-domain astrophysics, with a focus on black hole accretion disks and jets, tidal disruption events, and their connections to galaxies. She currently co-chairs the TDE & AGN science topical panel of the Einstein Probe Telescope.

封面圖片來源：

更多報告信息：

《物理》50年精選文章