Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session Q3: Invited Session: Condensed Matter Physics in Latin America II |
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Sponsoring Units: FIP Chair: Edmond L Berger, Argonne National Laboratory Room: 002AB |
Wednesday, March 4, 2015 2:30PM - 3:06PM |
Q3.00001: Spin dynamics with Solid State NMR and GPU calculations: Loschmidt Echoes, Intrinsic Decoherence and Quantum Dynamical Phase Transitions Invited Speaker: Horacio M. Pastawski After overviewing argentine Condensed Matter Physics outside the Metropolitan area I will focus on the Loschmidt Echo [LE], a concept developed and pursed at C\'{o}rdoba. It is the recovered fraction of a localized excitation after a spreading period followed by an imperfect time reversal procedure [1]. In Solid State NMR, the LE has allowed us to quantify the decoherence and irreversibility induced by an uncontrolled environment. Notably complex many-body dynamics makes the system particularly sensitive to environmental disturbances presenting a decoherence rate that becomes perturbation independent beyond some small threshold. These experiments and the theoretical analysis based on the Feynman's path integral, summarized at a tutorial level, fueled the field of dynamical quantum chaos [4]. The quest for a perturbation independent decoherence as an emergent phenomenon in thermodynamic limit, lead us to discuss other dynamical observables that depend non-analytically on the environment strength, i.e. that undergo a quantum dynamical phase transition QDPT [2]. GPU based high performance computing boosts the evaluation of the LE [3], allowing us to asses thermalization and how the Metal-Insulator transition (also a QDPT) emerges in interacting many-body systems. \\[4pt] [1] \textbf{\textit{Loschmidt Echo, }}A. Gousev, R.A. Jalabert, H.M. Pastawski and D.A. Wisniacki. \textit{Scholarpedia }\textbf{7}, 11687 (2012) \\[0pt] [2] \textbf{\textit{Environmentally induced quantum dynamical phase transition in the spin swap operation, }}G.A.\'{A}lvarez, E.P.Danieli, P.R. Levstein, and H.M. Pastawski, \textit{J. Chem.Phys. }\textbf{124}, 1 (2006)\\[0pt] [3] \textbf{\textit{Interaction-disorder competition in a spin system evaluated through the Loschmidt echo }}P.R. Zangara, A.D. Dente, A. Iucci, P.R. Levstein, and H.M. Pastawski, \textit{Phys. Rev. B} \textbf{88}, 195106 [Preview Abstract] |
Wednesday, March 4, 2015 3:06PM - 3:42PM |
Q3.00002: An Upgrade for the Brazilian Synchrotron Light Source: Are you Sirius? Invited Speaker: Antonio Jos\'e Roque da Silva The application of synchrotron radiation in a great variety of fields in general, and condensed matter in particular, has increased steadily worldwide. This, to a large extent, is a result of the availability of the much brighter third-generation light sources, which opened up new experimental techniques. Recently, new developments in accelerator technology are paving the way for even brighter sources, which are being named fourth-generation light sources. Sirius, the future new Brazilian synchrotron, is one of the first two such machines being currently constructed in the world. Its first light is expected by 2018. It is being planned to be a state of the art machine, providing tools for cutting edge research that are non existent today in Brazil. It is a project designed and executed by the Laborat\'{o}rio Nacional de Luz S\'incrotron -- LNLS, which was also responsible for the construction of the current second generation Brazilian light source, the first synchrotron in the southern hemisphere, still the only one in Latin America. In this talk an overview of the status of Sirius will be provided. [Preview Abstract] |
Wednesday, March 4, 2015 3:42PM - 4:18PM |
Q3.00003: Large area radiation detectors based on II VI thin films Invited Speaker: Manuel Quevedo-Lopez The development of low temperature device technologies that have enabled flexible displays also present opportunities for flexible electronics and flexible integrated systems. Of particular interest are possible applications in flexible, low metal content, sensor systems for unattended ground sensors, smart medical bandages, electronic ID tags for geo-location, conformal antennas, neutron/gamma-ray/x-ray detectors, etc. In this talk, our efforts to develop novel CMOS integration schemes, circuits, memory, sensors as well as novel contacts, dielectrics and semiconductors for flexible electronics are presented. In particular, in this presentation we discuss fundamental materials properties including crystalline structure, interfacial reactions, doping, etc. defining performance and reliability of II-VI-based radiation sensors. We investigate the optimal thickness of a semiconductor diode for thin-film solid state thermal neutron detectors. Besides II-VI materials, we also evaluated several diode materials, Si, CdTe,GaAs, C (diamond), and ZnO, and two neutron converter materials,10B and 6LiF. We determine the minimum semiconductor thickness needed to achieve maximum neutron detection efficiency. By keeping the semiconductor thickness to a minimum, gamma rejection is kept as high as possible. In this way, we optimize detector performance for different thin-film semiconductor materials. [Preview Abstract] |
Wednesday, March 4, 2015 4:18PM - 4:54PM |
Q3.00004: Condensed Matter Physics in Colombia is in its forties Invited Speaker: Angela Camacho Physics in Colombia started to develop in the 70's as a research part of basic sciences with the acquisition, at that time, of large research equipments such as x-rays and EPR. Experimental work was soon supplemented by theoretical investigations, which led to the formation of research groups in condensed matter. In the early 80's existed such groups in five universities. In this report we present, after a short history of the main steps that guided the initial research subjects, the major areas already developed and the minor research groups that are in the stage of consolidation. Currently this type of work is done at least in 20 universities. We also show the actual numbers of researchers, publications, PhD students and laboratories discriminated in gender to complete an overview of Condensed Matter Physics in Colombia. Finally, we present a short review of the main theoretical issues that have been worked in the last decade focusing on low dimensional systems, their structural and optical properties [Preview Abstract] |
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