The MIT DEPARTMENT OF PHYSICS presents

The 14th Annual Pappalardo Fellowships
in Physics Symposium

FRIDAY, MAY 8, 2015

2:00 - 5:00 PM


MIT Department of Physics
Pappalardo Community Room
Building 4, Room 349
Cambridge, MA

Five members of the Department's premier postdoctoral fellowship program, the Pappalardo Fellowships in Physics, will present highlights from their independent research projects.The talks are designed for the enjoyment of all members of the MIT physics community.

Refreshments available for attendees in the foyer of 4-349 beginning at 1:45 pm.

 

SCHEDULE OF SPEAKERS

  TIME SPEAKER TITLE & ABSTRACT
  1:45 pm   Refreshments for attendees served in foyer outside the Pappalardo Community Room
(4-349).
2:00 pm

Prof. Jeff Gore, MIT
Department of Physics;
2007-09 Pappalardo Fellow

Introductory Remarks
2:15 pm

Taritree Wongjirad,
2014-17 Fellow,
Experimental Nuclear & Particle Physics

Searching for Neutrino-less Double Beta Decay Using Quantum Dot Nanoparticles

There is currently much interest in the neutrino community to look for a yet-unobserved nuclear decay process known as neutrino-less double beta decay. This decay process involves the simultaneous transformation of two neutrons into two protons and two electrons. If seen, we would learn an important fact about the neutrino: that it is its own antiparticle. This fact would have consequences for not only particle physics but also cosmology.

I am working with Prof. Lindley Winslow and her group to build a new type of detector to look for this process. This detector will feature the use of a material known as quantum dot nanoparticles, which have a number of properties that can be useful in the search for neutrino-less double beta decay.

In this talk, I’ll discuss what neutrino-less double beta decay is and how quantum dots can be used to search for it.

  2:30 pm Question & Answer
2:45 pm

Inti Sodemann,
2014-17 Fellow,
Hard Condensed Matter Theory

The Nature of Spin Superfluidity and its Potential Uses

Superfluidity, a dissipationless collective flow of matter, is one of the most amazing phenomena displayed by physical systems on macro-scales. It is perhaps less well known that quantities other than particle density, for instance spin, can also exhibit superfluidity.

In this talk, I will discuss measurable manifestations of spin superfluidity and describe a proposed microelectronic device inspired on the idea of perfect spin-drag with a potential for extreme low-power consumption.

  3:00 pm   Question & Answer
3:15 pm

Meng Su,
2012-15 Fellow,
Theoretical Astrophysics

From Space to the Tibet Plateau: Probing the Mystery of the Universe in Gamma Ray and Microwave

Space gamma-ray astronomy was born here at MIT more than a half-century ago. A few gamma-ray satellites have operated since then–in particular the most recent Fermi Gamma-ray Space Telescope–and have proved the great potential of probing a wealth of questions among the most important themes of astrophysics, cosmology and fundamental physics. However, the low-energy range of gamma rays is still poorly covered after decades. PANGU (the PAir-productioN Gamma-ray Unit) is a small astrophysics mission with a wide field of view optimized for spectro-imaging, timing and polarization studies. It will map the gamma-ray sky at this crucial energy range with unprecedented spatial resolution.

Unlike GeV photons, which could only be detected above the atmosphere, observations of the Cosmic Microwave Background (CMB) have been achieved with less costly ground-based telescopes at the South Pole and the Atacama desert in Chile. I'll describe a unique site located at the Tibet Plateau that opens the northern sky for future ground-based CMB telescopes, to search for signatures of inflation–a period of accelerated expansion in the very early Universe and to probe the structure growth of our Universe.

  3:30 pm Question & Answer
3:45 pm I N T E R M I S S I O N
4:00 pm

Benjamin Safdi,
2014-17 Fellow,
Theoretical High Energy Physics

Directional Antineutrino Detection

I will propose the first event-by-event directional antineutrino detector using inverse beta decay (IBD) interactions on hydrogen, with potential applications including monitoring for nuclear nonproliferation; spatially mapping geoneutrinos; characterizing the diffuse supernova neutrino background; and searching for new physics in the neutrino sector.

The detector, called SANTA (Segmented Antineutrino Tomography Apparatus), consists of adjacent and separated scintillator planes. Its design is a straightforward modification of existing antineutrino detectors, and I will describe current efforts towards building a prototype.

  4:15 pm Question & Answer
4:30 pm Yoav Lahini,
2012-15 Fellow,
Experimental Soft Condensed Matter & Biophysics

Towards Optical Measurements of Virus Self-Assembly: How Does a Virus Grow?

Viruses are among Nature’s most dangerous parasites, sometimes overwhelming their host simply by how rapidly they replicate. Some viruses are also surprisingly simple, consisting only of a single molecule of genomic information (DNA or RNA) surrounded by a protective shell composed of many copies of the same protein.

Although the structures of infectious viruses are known in atomic-resolution detail, the mechanism by which they spontaneously and perfectly assemble themselves from a randomly fluctuating soup of proteins and viral genome is still mostly unknown. The reason for this gap in our knowledge is a gap in measurement capabilities: viruses are very small, only few tens of nanometers in diameter, and the self-assembly process is fast, taking about a thousandth of a second. Even using the most advanced measurement techniques, it is hard to be both sensitive enough and fast enough to resolve such processes.

I will describe the realization of a new, ultra-sensitive and ultra-fast technique, with which we have been able to detect and track single, unlabeled viruses as small as 26 nanometers in diameter, freely diffusing in solution, at rates that are faster than the expected self-assembly times. I will outline some of the preliminary results, and the route we intend to take in order to resolve the assembly process.

  4:45 pm Question & Answer
5:00 pm F I N I S

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