Department Calendar

Week of November 11, 2018

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All day
Before 1am
Gianluca Zoccarato, UPENN

Gianluca Zoccarato, UPENN

Mon, 11/12/2018 - 2:10pm
Pupin Hall Theory Center, 8th Floor


"F-theory and dark energy"
I will present compactifications of F-theory a four dimensional spacetime with spatial slices that have the topology of 3-sphere. These solutions may be used as a starting point for solving some of the known problems of the cosmological constant. The 3-sphere is the target space of an SU(2) WZW model which allows for an exact worldsheet analysis. The compactification space is chosen to be a Spin(7) manifold thus giving "half-supersymmetry" in 4D. I will discuss cosmological solutions that resemble Einstein static Universe. These solutions are actually unstable and can either contract or expand, leading to possibly interesting cosmological scenarios. Finally I will discuss the implications of these scenarios for particle physics.

Title & abstract TBA

About the speaker

Gianluca's research interests include string phenomenology and string compactifications.

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11/12/2018 - 2:10pm
Luca Grandi, University of Chicago

Luca Grandi, University of Chicago

Mon, 11/12/2018 - 4:15pm
428 Pupin Hall


"The XENON Program: at the forefront of Dark Matter Direct Detection"

Dark Matter is out there, waiting to be detected. I will present the XENON way of doing it - i.e. with two-phase Time Projection Chambers (TPC) sensitive to possible dark matter interactions inside an ultra-low background Liquid Xenon (LXe) target. The XENON1T detector has been operating at Laboratory Nazionali del Gran Sasso since Spring 2016, and with 3.3 tons of xenon it is presently the largest LXe dark matter experiment in operation. I will guide you through the XENON1T science program, presenting the experimental challenges and the most recent results. Finally I will discuss the path towards its upgrade, XENONnT, presently under construction at Gran Sasso National Laboratory and with early science data expected in mid-2019.

About the speaker

Luca Grandi studies fundamental physics, of a type that is able to change one’s way of looking at the surrounding world and provide a deeper understanding of how nature works. He has also been attracted by small-scale, human-size experiments, and enjoys designing and operating detectors and analyzing their collected data. These interests led him toward the field of rare events physics and, more specifically, toward dark matter direct searches. This area of research has great potential for discovery and the capability of providing experimental results that affect the foundation of our physics theories.

To date, his activities have been focused on the development of liquid argon two-phase time projection chamber (TPC) technology for dark matter direct detection. He was involved in the design, construction, and operation of the WArP-2.3kg prototype, the first and only argon detector to have set a limit on the WIMP (weakly interacting massive particles) interaction rate. Together with colleagues from other institutions, he cofounded the DarkSide project, which combines two-phase argon and organic liquid scintillator technologies. DarkSide-50, the first physics detector of the DarkSide family, is being deployed at Gran Sasso Underground Laboratory in Italy, and has become an international collaboration involving other institutions from the United States and Europe.

Grandi completed his PhD course of study in physics at Pavia University in Italy. 

More details on Gary's research can be found here.

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11/12/2018 - 4:15pm
Kazu Terao, SLAC National Laboratory

Kazu Terao, SLAC National Laboratory

Wed, 11/14/2018 - 1:00pm
705 Pupin Hall


"Deep Neural Network Applications for Liquid Argon Time Projection Chamber Data Reconstruction"

Liquid Argon Time Projection Chambers (LArTPCs) are capable of recording images of charged particle tracks with breathtaking resolution.  Such detailed information will allow LArTPCs to perform accurate particle identification and calorimetry, making it the detector of choice for many current and future neutrino experiments.  However, analyzing such images can be challenging, requiring the development of many algorithms to identify and assemble features of the events in order to reconstruct neutrino interactions.  In the recent years, we have been investigating a new approach using deep neural networks (DNNs), a modern solution to a pattern recognition for image-like data in the field of Computer Vision. A modern DNN can be applied for various types of problems such as data reconstruction tasks including interaction vertex finding, pixel clustering, and particle/topology type identification. We have developed a small inter-experiment collaboration to share generic software tools and algorithms development effort that can be applied to non-LArTPC imaging detectors. In this talk I will discuss the challenges of LArTPC data reconstruction, recent work and future plans for developing a full LArTPC data reconstruction chain using DNNs.

About the speaker

Kazu is currently involved in the MicroBooNE experiment as an associate staff scientist member in the Elementary Particle Physics (EPP) division at SLAC national accelerator laboratory. Previously he worked on the same experiment was a post-doctoral research scientist at Nevis Laboratories at Columbia University. Before MicroBooNE, Kazu worked on Double Chooz during my Ph.D at MIT, and KamLAND while at U.C. Berkeley for his undergraduate studies.

Currently, Kazu's focus is to apply a machine learning technique, in particular deep neural networks to perform data recontruction tasks and physics analysis.

More details can be found here.

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11/14/2018 - 1:00pm
Leonid Rokhinson, Purdue

Leonid Rokhinson, Purdue

Fri, 11/16/2018 - 5:00pm
11M North West Corner


Nano-Optics Seminar
"Experimental search for non-Abelian excitations"

I will start with an introduction into the physics of Majorana fermions in semiconductor/superconductor hybrids and description of our experiments where the fractional ac Josephson effect, a hallmark of topological matter, has been observed. I will briefly discuss challenges facing the field which make manipulation and demonstration of non-Abelian statistics extremely difficult.

In the second part I will introduce a new platform based on spin transitions in the fractional quantum Hall effect regime where parafermions - higher order non-abelian excitations - can be realized. Local (gate) control of spin transition allows formation of isolated domain walls, which consist of counter-propagating edge states of opposite polarization with fractional charge excitations. When superconductivity is induced into such a domain wall from superconducting contacts via proximity effect, parafermions are expected to be formed at the domain wall boundaries. In a multi-gate device a re-configurable network of domain walls can be formed allowing creation, braiding, manipulation and fusion of parafermions. In respect to the quantum computing application parafermons are more computationally intense than Majoranas and are a building block for Fibonacci fermions, even high order non-Abelian particles that can perform universal gate operations within the topologically protected subspace.
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11/16/2018 - 5:00pm
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