量子计算软硬件研究的一些新进展 | 本周物理学讲座学术资讯

1量子计算软硬件研究的一些新进展

报告人：郭国平，中国科学技术大学

时间：12月20日（周四）16:00

单位：清华大学

地点：理科楼1112教室

报告将主要介绍我们团队(中国科大和本源量子)在半导体量子芯片中单、双、三量子比特逻辑门的构造和实现;操控量子比特的量子测控系统;各类功能量子软件应用程序;64位量子虚拟机和量子云平台等半导体量子计算实验研究和相关软硬件研究方面的一些最新进展。

2Axion and hidden photon dark matter detection with multilayer optical haloscopes

报告人：Junwu Huang，The Perimeter Institute for Theoretical Physics

时间：12月18日（周二）14:00

单位：清华大学

地点：物理系理科楼B315

In this talk, I will discuss a theoretical proposal for a new class of detectors for dark photon and axion dark matter at frequencies from the infrared through the ultraviolet based on dielectric haloscopes and high precision and efficiency single photon detectors, as well as some recent experimental progress.

A well-motivated class of dark matter candidates including axions and dark photons takes the form of coherent oscillations of a light bosonic field. If the dark matter couples to Standard Model states it may be possible to detect it via absorptions in a laboratory target. Current experiments of this kind include cavity-based resonators that convert bosonic dark matter to electromagnetic fields operating at microwave frequencies. In periodic photonic materials, bosonic dark matter can efficiently convert to detectable single photons. With feasible experimental techniques, these detectors can probe significant new parameter space for axion and dark photon dark matter in the 0.1-10 eV mass range.

3Langevin QMC algorithm for strongly interacting electron-phonon systems ——The phase diagram of two-dimensional model with long range interactions

报告人：G. G. Batrouni，University of Nice-Sophia Antipolis

单位：北京师范大学
时间：12月18日（周二）15:30

地点：物理楼106

I present a quantum Monte Carlo algorithm for electron-phonon systems based on the Langevin equation. I discuss systematic errors due to discretization of Langevin time, autocorrelation, and the
discretization of imaginary time (Trotter-Suzuki). I will also discuss and implement Fourier acceleration to speed up convergence. I show that the execution time scales almost linearly with system size and demonstrate that, in the case of the Holstein model, the results are in excellent agreement with determinant QMC (which has cubic dependence on system size). We then use this algorithm to show, for the first time, the phase diagram of the strongly interacting electron-phonon system in two dimensions with long range interactions.

4Extragalactic Cosmic Accelerators Through the Eyes of Ground-Based Gamma-Ray Telescopes

报告人：Qi Feng，Columbia University

时间：12月19日（周三）10:00

单位：清华大学

地点：蒙民伟科技南楼S727

Some of the fastest and most energetic flares from active galactic nuclei (AGN) have been observed by ground-based gamma-ray telescope arrays, like the Very Energetic Radiation Imaging Telescope Array System (VERITAS). These flares provide strong constraints on the size and Doppler factor of the emitting regions in highly relativistic AGN jets. However, it is not an easy task to pinpoint the location of gamma-ray emitting region because of the limited angular resolution of the instruments. Multiwavelength observations contemporaneous to the gamma-ray flares make this task possible. We present recent results from the VERITAS AGN observation program, highlighting long-term and short-term variabilities of blazars with multiwavelength and multimessenger observations. We also show the progress of the prototype Schwarzschild-Couder telescope for the Cherenkov Telescope Array, as well as novel gamma-ray data analysis techniques using machine learning.

5Terahertz Spectroscopy of Quantum Spin Dynamics in Low-Dimensional Quantum Magnets

报告人： Zhe Wang，Helmholtz-Center Dresden-Rossendorf, Dresden, Germany

时间：12月19日（周三）10:00

单位：中科院物理研究所

地点：M253会议室

Quantum states in low-dimensional spin systems are characterized by their characteristic spin dynamics. In this seminar, I will talk about our recent works on terahertz spectroscopy of quantum spin dynamics in low-dimensional quantum magnets, such as quantum spin dimer, quantum spin chain, and two-dimensional frustrated magnet. I will briefly introduce how spin excitations in a spin system could be probed and magnetic interactions be determined by terahertz spectroscopy. The main focus of the seminar will be on dynamics of a spin-1/2 Heisenberg-Ising antiferromagnetic chain for longitudinal and transverse magnetic fields. In addition to the well-known low-energy spin dynamics, I will show that high-energy excitations, such as confined spinons and Bethe strings, are realized in the spin chain system for a longitudinal field. Moreover, in a transverse field, our study of spin dynamics allowed us to identify a quantum critical point of the transverse-field Ising-chain. The experimental results are very well compared to theoretical calculations, as the spin chain model is exactly solvable. In addition, spin dynamics in α-RuCl3, a candidate for realizing quantum spin liquid, will be discussed.

6光电镊技术的物理和生物应用

报告人：张帅龙，加拿大多伦多大学

时间：12月19日（周三）14:00

单位：北京师范大学

地点：物理楼106

光电镊技术是一种新型的光流体技术，利用光致介电泳效应，可以实现对微小物体的精确操控。讲座的第一部分将介绍如何利用光电镊技术组装不同的光电器件，包括银纳米线，金属微球和半导体激光器。实验发现这些光电器件在光电镊系统中受到很强的操控力，可以被精确的操控和组装，证明光电镊是一种有效的光电器件微组装系统。讲座的第二部分将介绍如何利用光电镊技术对生物细胞进行操控和分选，在单细胞层面研究细胞间的竞争和通讯机制。此外，光电镊系统也可以对小型机器人进行操控，利用机器人对细胞进行复杂的控制和移动。这些结果都证明光电镊是一种高效的细胞操控技术，可在单细胞层面通过精确控制实验条件，研究细胞性质并理解细胞的复杂行为。这些实验结果都有相应的仿真作为支持。

7Conducting Oxide Interfaces: New Opportunities for Electronics and Electrocatalysts

报告人：Yunzhong Chen，Technical University of Denmark

时间：12月20日（周四）10:00

单位：中科院物理研究所

地点：M253会议室

The recent progress in the epitaxial growth of complex oxide thin films with precise control on atomic scale has provided us unforeseen opportunity to design heterostructures with on-demand functionalities. Herein, I will discuss our recent discoveries of metallic interfaces or two-dimensional electron gases (2DEGs) at the interface between two insulating complex oxides, such as gamma-Al2O3 (GAO) epitaxially grown on SrTiO3 (STO) [1,2] as well as the large enhancement of the interfacial electron mobility [3, 4] and quantum Hall effect [5] at modulation-doped oxide interfaces. Perspectives on oxide electronics [6] as well as oxide heterointerfaces for superior electrocatalysts will be also discussed.

8Changing-look Quasars: Discoveries and Challenges

报告人： Xuebing Wu，Peking University

时间：12月20日（周四）14:00

单位：清华大学

地点：蒙民伟科技南楼S727

The discovery of changing-look (CL) AGNs, with the appearance or disappearance of broad Balmer emission lines in the UV/optical spectra within a few years, challenges our understanding of the AGN unification model. We present a sample of 21 new CL AGNs at redshifts between 0.08 and 0.60, which doubles the number of such objects known to date. These new CL AGNs were discovered by several ways, from (1) repeat spectra in the SDSS, (2) repeat spectra in the LAMOST and SDSS, and (3) photometric variability and new spectroscopic observations. The continuum flux in the optical and mid-infrared becomes brighter when the CL AGNs turn on. The optical and mid-infrared variability is not consistent with the scenario of variable obscuration in 10 CL AGNs at more than 3-sigma confidence level. We confirm a bluer-when-brighter trend in the optical. However, the mid-infrared WISE colors W1 - W2 become redder when the objects become brighter in the W1 band, possibly due to a stronger hot dust contribution in the W2 band when the AGN activity becomes stronger. The physical mechanism of type transition in CL AGNs is still unknown, but preferred to be related to the accretion rate change in the inner part of accretion disks around super massive black holes.

9集成型光学轨道角动量器件及其应用

报告人：冯雪，清华大学

时间：12月20日（周四）14:00

单位：清华大学

地点：物理系理科楼C302

人们很早就认识到每个光子能够携带线动量，然而直到1992年，Allen 等人才发现具有角向相位分布的光波携带有轨道角动量。在2012年，英国布里斯托大学、美国阿尔卡特-朗讯公司的贝尔实验室联合美国加州大学戴维斯分校以及我的研究小组几乎是同时开展了集成型光学轨道角动量器件的探索性研究工作。

10Superanomalous skin effect for surface plasmon-polaritons

报告人：Sufei Shi

时间：12月20日（周四）15:30

单位：中科院理论物理所

地点：Conference Room 6620, ITP new building

It is commonly assumed that surface plasmon-polariton (SPP) excitations on a metal-dielectric interface decay exponentially inside the metallic sample. Here we show that at high frequency and wave vector the SPP field decays much slower, being inversely proportional to the distance to the interface modified by an additional logarithmic factor. This dependence differs from the standard anomalous skin effect where field decays as (1/z)^2. We provisionally referred to it as “superanomalous”. Its origin is the non-locality and the logarithmic singularity of the dielectric permittivity in metals. This type of decay is pronounced for SPP modes of higher frequencies, but is suppressed for red – infrared light range.

11Data Oriented GRB Research and the Gravitational Wave GRBs

报告人：Binbin Zhang，Nanjing University

时间：12月20日（周四）16:00

单位：北京大学

地点：KIAA-PKU Auditorium

In this talk, I will briefly discuss our recent data oriented research works in GRB field. I will first review our fully automatic GRB data analyzing system. I will then talk several case studies that directly utilized the results from our system. In particular, I will focus on prompt emission data of the gravitational wave GRB 170817A and discuss our current understanding of this first NS-NS merger event, including its event rates, ejecta topology, radiation mechanism and what can learn from the 1.7 s time delay between the GRB and the gravitational signal.

12Lectures on solvable irrelevant deformations of 2d quantum field theories

报告人：Yunfeng Jiang，CERN

时间：12月21日（周五）14:00

单位：中科院理论物理所

地点：ITP New Building 6620

The main topic of these three lectures is on recent developments in solvable irrelevant deformations of 2d quantum field theories. In the first lecture, I will introduce the T-Tbar deformation of 2d QFT. Special emphasis will be put on the deformed Lagrangian and the exact solvability of the spectrum. In the second lecture, I will focus on the torus partition sum of the T-Tbar/J-Tbar deformed CFTs and modular invariance/covariance. In the third lecture, I will present different perspectives on the T-Tbar deformation including the relations to random geometry, Jackiw-Teitelbolm gravity and holography.

13气体探测器的过去，现在与未来

报告人：谢一冈，高能物理所

时间：12月21日（周五）13:30

单位：中国科学院大学

地点：雁栖湖校区教1-114

更多报告信息：中国物理学会期刊网学术讲座列表

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