報告人：吳嶽良 院士，中國科學院大學
時間：4月4日（周三）18:30
單位：中國科學院大學
地點：雁棲湖校區教1-306
自1915年愛因斯坦創立廣義相對論後，他一直嘗試探尋統一場論，儘管未能取得成功，但關於統一場論的理念一直延續至今。統一場論成為一代又一代理論物理學家和數學家追求的夢想。超統一場論的建立遵從兩個基本指導原則：一是基本粒子的內稟量子數和獨立自由度決定時空的維度和結構；二是描述自然規律的作用量遵循規範不變原理和坐標選取無關。超統一場論使得所有已知的基本粒子統一成為十九維超時空中的單一基本粒子——馬約拉納型超旋量場，其旋量結構由基本粒子超自旋荷的量子特性所決定，所有已知的四種基本相互作用由超旋量場的超自旋規範對稱性統一支配，並由超自旋規範場和與之相伴隨的超引力場統一描述。超統一場論的建立涉及對時空觀念、幾何觀念和宇宙觀念以及物質觀念和能量觀念的重新認識。該理論預言新的矢量型夸克和輕子、鏡像夸克和輕子、多重態規範矢量玻色子和有效標量玻色子等新粒子以及自旋力和標度力等新的相互作用力的存在。
2 Precision Higgs Physics
報告人：Jian Wang, Technical University of Munich
時間：4月3日（周二）13:00
單位：清華大學物理系
地點：理科樓C302報告廳
The Nobel Prize in Physics 2013 was awarded jointly to Fran？ois Englert and Peter W. Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was con？rmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider」. Why is the Higgs boson so important?
What is the present status of our understanding of such a particle?
What is the plan to study its properties in future?
I will talk about these topics based on some of my previous work.
報告人：李海波、房雙世，中科院高能物理所
時間：4月3日（周二）13:30
單位：中國科學院大學
地點：雁棲湖校區-教1-113
報告人：Mokhtar Chmeissani，CERN
時間：4月3日（周三）15:00
單位：中科院高能物理所
地點：化學樓305
Current Positron Emission Tomography (PET) scanner have limited image resolution which is in part due to the intrinsic limits set by the PET physics and in part due to the design and the material used in the PET scanner. We present a novel detector module, based on stack of pixel CdTe sensor, to reduce significantly the limitation coming from spatial and energy resolution. Each module detector has 4000 voxel (independent channels). Each voxel is 1mm x 1mm x 2mm of CdTe bonded to a dedicate pixel channel. Each ASIC (100 channels) has one TDC with time resolution of 1 ns. Each channel has its own pre-amp, shaper, discriminator, and 10 bits ADC. Each triggered voxel send its energy digitized appended with time stamp. This convert the novel detector into a true 3D gamma detector as it can precisely indicate the exact coordinated in space ( x,y, and z) of the impact point of the gamma photon.
報告人：Csaba Csaki，Cornell University
時間：4月3日（周二）15:00
單位：中科院理論物理所
地點：ITP New Building 6420
While the current vacuum energy of the Universe is very small, in our standard cosmological picture it has been much larger at earlier epochs. We try to address the question of what are possible ways to try to experimentally verify the properties of vacuum energy in phases other than the SM vacuum. One promising direction is to look for systems where vacuum energy constitutes a non-negligible fraction of the total energy, and study the properties of those. Neutron stars could be such systems, and we discuss how to use the recent observation of neutron star mergers to try to learn about the inner core of the neutron star which may be dominated by vacuum energy.
報告人：Joseph Falson，Max Planck Institute for Solid State Research
時間：4月4日（周三）10:00
單位：北京大學量子材料科學中心
地點：物理樓西563
Landau levels (LL) in high quality two-dimensional electron systems (2DES) host an array of fractionalized electronic phases whose nature depends on their polarization in competing orbital and spin degrees of freedom.The LL index (N) plays an important role in determining the ground state of a half filled level, with the emergent Fermi-sea that forms in N=0 to displaying instabilities towards a gapped phase in N=1 and a nematic stripe phase in N=2. In this presentation I will discuss the physics of high mobility ZnO-based 2DES at filling factor n= 5/2 as the orbital character of electrons is continuously tuned between N=1 and 0 character. In stark contrast to the naive expectation of a first-order transition between level-polarized states, a rich cascade of five phases with distinct transport features are resolved as charge is gradually transferred between the two levels. In addition to incompressible (in N=1) and compressible (in N=0) states, intermediate polarizations witness additional compressible, incompressible and anisotropic nematic phases. The emergence of these unexpected phases in an orbitally mixed regime when the levels are near degeneracy motivates speculation this is a promising system for realizing unanticipated flavors of inter-level coherent states at fractional filling factors.
報告人：畢嘯天（畢導）
時間：4月4日（周三）14:00
單位：中科院物理所
地點： M234報告廳
代表作品：《一個清華博士在供暖前給廣大學子最中肯的建議》，《微信紅包先搶和後搶的差距居然這麼大！春節搶紅包的大數據分析》，《吃了幾十個西瓜後，我終於發明了能避開所有瓜籽的科學吃瓜法！》，《聽說香蕉和棗一起吃會看到人生的走馬燈？實驗揭秘最最最噁心的吃法配方》
報告人：Dong Lai，Cornell University
時間：4月4日（周三）16:00
單位：北京大學科維理天文與天體物理研究中心
地點： KIAA-PKU Auditorium
Circumbinary disks have been observed in a number of young stellarsystems, and are the birth place for circumbinary planets found by theKepler misssion. They are also expected to exist around supermassiveblack hole binaries as a consequence of accretion from theinterstellar medium following galaxy mergers. I will discuss recent works on numerical modeling of circumbinary accretion, focusingshort-term and long-term variabilities, and angular momentum transferbetween the disk and the binary -- the result suggests that thelong-standing notion of binary orbital decay driven by circumbinarydisk may be problematic. Implications for planet formation/migrationaround stellar binaries will be noted. I will also discuss thedynamics and evolution of inclined/warped disks in binaries andconnect with recent observations of protoplanetary disks andcircumbinary planets.