2018 Fall Seminar List

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Editing 2018 Fall Seminar List

== Fall 2018 LeCosPA Cosmology and Particle Astrophysics Seminars ==

Location : Room 812, Astro-Math Building, NTU

Time : 11:00 am - 12:00 am, Monday

Organizers : Dr. Matsumoto, Jiro & Dr. TC Liu


Date Name Title Affiliation File
Sep/17
Ryan Wang
Liquid noble gas for direct dark matter detection
abstract :Liquid noble gas detector becomes more and more popular in the particle physics community due to its long term stability , hight light yield and fast response times. The powerful pulse shape discrimination (PSD) of the noble gas provides great tool to distinguished unwanted background events (electronic recoil) from desired signals (nuclear recoil). In addition, electron signal produced at interaction site can be extracted when applying the electric field. This gives the opportunity to construct the Time Projection Chamber(TPC) using liquid noble gas, i.e. dual phase detector. In this talk, I will review the basic principle of operating the liquid noble gas detector as well as the current status of dark matter direct detection
Brandies University File:RyanWang2018.pdf
Oct/1
Dong-han Yeom
Hawking radiation and the thermal interpretation of instantons
I will first discuss that Hawking radiation is indeed a kind of instantons. Such an instanton can be related to the path integral of particles, which was developed by Hartle and Hawking. In order to justify Hawking radiation, a choice of propagators is very important. From this analysis, we conclude that the thermal interpretation of Brown and Weinberg, that was originally proposed in de Sitter space, can be further justified. This is an interesting interplay between the particle tunneling picture and the instanton picture.
APCTP
Oct/8
K-H Huang
An Example of Using Convolutional Neural Network to Correct Gamma-ray Energy MeasurementE
abstract
affliation slides
Oct/15
Petr Valenta
Relativistic Mirrors in Laser-Plasma Interaction
Relativistic flying mirrors (RFM) are thin dense electron or electron-ion shells travelling through plasma with velocities close to the speed of light in vacuum [1]. A counter-propagating laser pulse can be reflected from such mirror, resulting in its energy and frequency change. Due to the double Doppler effect, the reflected wave is compressed, amplified and its frequency is up-shifted by the factor proportional to the Lorentz factor squared. RFM can be realized using strongly non-linear Langmuir waves generated by short intense laser pulses in underdense plasmas. Adjusting the properties of the target and the counter-propagating laser beam allows one to control the output parameters of the reflected light. Various schemes described in theoretical as well as experimental studies have proven the feasibility of this concept [2].

Regarding the possible applications, the concept of RFM is very promising for generation of compact and tunable sources of coherent electromagnetic radiation from X-ray to gamma-ray range of photon energies. Such sources are of great demand for applications in diverse fields [3, 4, 5]. The relativistic mirrors formed in inhomogeneous plasmas might be also exploited to study the Unruh effect and the information loss paradox associated with black hole Hawking evaporation at the terrestrial laboratory conditions [6].

[1] S. V. Bulanov et al., Plasma Sources Sci. Technol. 25, 053001 (2016) [2] S. V. Bulanov et al., Physics - Uspekhi 56, 429 (2013) [3] F. Krausz and M. Ivanov, Rev. Mod. Phys. 81, 1 (2009) [4] R. Neutze et al., Nature 406, 752 (2000) [5] T. Zh. Esirkepov et al., EAS Publ. Ser. 58, 7 (2012) [6] P. Chen and G. Mourou, Phys. Rev. Lett. 118, 045001 (2017)

ELI Beamlines File:Valenta slides.pdf
Oct/22
Keiichi Umetsu
Testing Dark Matter Models with Gravitational Lensing
In this talk, I will discuss how the predicted properties of

dark-matter (DM) halos can be examined and tested using various effects of gravitational lensing, such as weak shear lensing, weak magnification lensing, strong lensing, and the moving lens effect. I will present recent results from applications of gravitational lensing to observations of galaxy clusters, the largest class of DM halos. Possible topics to be covered include the density structure of DM in quasi-equilibrium halos, the asphericity of DM halos, the splashback feature in outskirts of DM halos, and the recent discovery of the universal fundamental plane (FP) relation in cluster-scale DM halos.

ASIAA
Oct/29
Hiroyuki Kitamoto
Schwinger Effect in Inflaton-Driven Electric Field
In a four dimensional inflation theory, a persistent electric field can be established by making the inflaton coupled to the gauge field like a dilaton. We investigate the pair production of scalar particles in the inflaton-driven electric field. In particular, we evaluate the induced current due to the pair production. The presence of the dilatonic coupling ensures the validity of the WKB approximation at the past and the future infinities, without tuning constant parameters. Thus, the semiclassical description is applicable in evaluating the induced current. Solving the field equations with the induced current, we evaluate the first-order backreaction to the electric field. It turns out that the electric field decreases with the cosmic expansion. The result indicates that the no-anisotropic hair theorem for inflation holds true regardless of whether the dilatonic coupling is present or not.
NCTS, NTHU File:LeCosPA2018.pdf
Nov/12
Wen-Yu Wen
Many roads lead to GUP
In this talk, I will show that different effective theories of quantum gravity may lead to different versions of Generalized Uncertainty Principle.
CYCU
Nov/19
Sadakazu Haino
KAGRA and up-coming world-wide gravitational wave detector network
abstract
affliation
Nov/26
Mariam Bouhmadi-Lo ́pez
On our way to unmask the late-time acceleration of the Universe
We will present several proposals to describe the late-time acceleration of the universe within the framework of general relativity and beyond it. In some of these models, we will see how the cosmological perturbations behave and how well they fit the data. If time allows, we will as well discuss dark energy related singularities.
University of the Basque Country UPV/EHU
Dec/3
Shin-Shan Eiko Yu
Search for dark matter in pp collisions with CMS
Searches in CMS for dark matter in final states with invisible particles recoiling against jets, top/bottom quarks, Ws, Zs, photons, Higgs bosons are presented. Various topologies are explored, covering several specific dark-matter production modes. The combination in a simplified-model framework of various searches for direct dark matter production with the CMS detector is discussed, highlighting sensitivities of the analyses under various assumptions of DM production and complementarities with non-DM analyses.
NCU
Dec/10
Yoji Koyama
Soft hair of dynamical black hole and Hawking radiation
Soft hair of black hole has been proposed recently to play an important role in the resolution of the black hole information

paradox. Recent work has emphasized that the soft modes cannot affect the black hole S-matrix due to Weinberg soft theorems. However as soft hair is generated by supertranslation of geometry which involves an angular dependent shift of time, it must have nontrivial quantum effects. We consider supertranslation of the Vaidya black hole and construct a non-spherical symmetric dynamical spacetime with soft hair. We show that this spacetime admits a trapping horizon and is a dynamical black hole. We find that Hawking radiation is emitted from the trapped horizon of the dynamical black hole. The Hawking radiation has a spectrum which depends on the soft hair of the black hole and this is consistent with the factorization property of the black hole S-matrix.

NCTS, NTHU File:LeCosPA 2018.pdf
canceled
Tc Liu
The fingerprint of extra high energy cosmogenic neutrinos
abstract
LeCosPA, NTU
Canceled
Hsi-Yu Schive
TBA
abstract
NTU
Jan/7
Akira Matsumura
Detectability of Bell-CHSH nonlocality by two spin detectors with optimal local filters
Abstract : The detection problem of quantum non-local correlation by two spin detectors is investigated. First we review the detection model of quantum entanglement of the Minokowski vacuum. It is shown that the entanglement between two spacelike points for some initial conditions of detectors is observed. Next we consider the detection of Bell nonlocaliy which is known as an important quantum correlation. Unlike the detection of entanglement, we need a local filtering operation to observe the Bell nonlocality. The local filtering operation is a probabilistic process performed by local observers and hence the detection of Bell nonlocality is probabilistic. Through the analysis of the Bell nonlocality detection, we find the relation between the detection probability and the detectable region of Bell nonlocality.
Nagoya university


Jan/21
Y.Y. Chang
SuperCDMS SNOLAB and Future Low-Mass Dark Matter Searches
abstract: In recent years, development in dark matter (DM) phenomenology below weak/WIMP scale has been booming. I will begin by discussing the rich phenomenology and rising interest in low-mass DM candidates, e.g. dark photon. I will then introduce SuperCDMS SNOLAB, one of the leading next generation experiment for DM direct detection. It will search for DM mass in 0.5-10 GeV range with a projected sensitivity down to 10^-43 cm^2 DM-nucleon scattering cross section. It utilizes cryogenic Ge/Si crystal with superconducting Transition Edge Sensor (TES) for phonon-mediated recoil detection, and it will begin data taking in 2020. The second half of the talk will be focused on the ongoing R&D and proposed concepts beyond SuperCDMS SNOLAB. I will introduce Kinetic Inductance Detector (KID) as a promising alternative to TES for future larger scale, high resolution, MeV-scale DM searches. Finally, I will briefly discuss recent proposals for new cryogenic target materials and conclude the talk with known/potential limitations and other future prospects toward the complete search for low-mass DM.
Calteh



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