The 16th Annual Pappalardo Fellowships
in Physics Symposium

THURSDAY, MAY 18, 2017

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 1:30 pm.



  1:30 pm   Refreshments for attendees served in foyer outside the Pappalardo Community Room
2:00 pm

Mehran Kardar, Francis Friedman Professor of Physics

Introductory Remarks
2:15 pm

Sanfeng Wu,
2016-2019 Fellow
(Experimental Condensed Matter Physics)

A Route to Quantum Knots with Anyons

A knot cannot change its topological property if its string doesn’t break, which is a property that makes knots a robust system for recording information. In fact, string knots were used for information storage and communication in a number of ancient cultures prior to the development of writing systems.

In this talk, I will discuss how it is possible to tie a "quantum knot" using exotic particles called anyons. Such a scheme can be used to code information in the quantum world that is immune to errors. Thus far, a quantum knot has not yet been tied in an experiment. However, recent theoretical and experimental progress has triggered a global competition to do so. I will present our recent efforts at MIT to identify a new quantum material suitable for tying a quantum knot.

  2:30 pm Question & Answer
2:45 pm

Rachel Carr,
2016-2019 Fellow
(Experimental Nuclear & Particle Physics)

Can we track down dark matter with cosmic antideuterons?

More than seventy years after the existence of dark matter was inferred, the identity of this abundant but scarcely interacting substance remains unknown. While many experiments look for interactions of dark matter particles in earthbound detectors or seek to create these particles with accelerator beams, we can also watch the sky for products of dark matter annihilation or decay elsewhere in the galaxy. Antideuterons—the antimatter correlate of deuterium nuclei—are a particularly appealing search target because known astrophysical processes contribute essentially no background.

The General Antiparticle Spectrometer (GAPS) will perform the first dedicated search for antideuterons in cosmic rays observed on a long-duration balloon flight over Antarctica. At MIT, we are developing the semiconductor devices that will form the heart of this novel detector.

  3:00 pm   Question & Answer
3:15 pm

Carl Rodriguez,
2016-2019 Fellow
(Theoretical Astrophysics)

Understanding the Origins of LIGO's Gravitational Waves

Last year, LIGO detected gravitational waves from merging binary black holes, with many more detections expected by the end of the decade. But where did these binaries form, and how did the black holes get close enough to actually merge?

In this talk, I will describe some of my past and future work towards answering these questions. I will show how the spins of merging black holes encode information about their history, allowing us to discriminate between different theoretical models for binary black hole formation. Further, I will explain how the next few years promise to revolutionize our understanding of black hole astrophysics as we head into the era of gravitational-wave astronomy.

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

Richard Fletcher,
2016-2019 Fellow
(Atomic Physics)

Quantum Simulation with Ultracold Atoms

In an ideal gas, every constituent member follows a single-particle trajectory, and the behavior of the whole cannot be more than the sum of its parts. Once interactions are introduced, the concept of collective behavior becomes meaningful, whereby a macroscopic phenomenon such as superfluidity emerges from the complexity of the underlying microscopic physics. One of the great goals of modern physics is to elucidate how this emergence occurs.

When a quantum fluid is restricted to move in two dimensions, one might imagine that its behavior becomes simpler. In contrast, the loss of spatial freedom results in the emergence of a host of new intriguing phenomena. Superfluidity, normally associated in three-dimensions with the emergence of a global order in which all particles flow in unison, is instead mediated by changes in the topology, or shape, of the fluid. Another example is the behavior of a two-dimensional electron gas subjected to strong magnetic fields, in which system properties display a robust quantization, and become locked to specific values determined by fundamental constants.

In this talk, I will give an overview of efforts to address these paradigmatic quantum states, using gases cooled to temperatures ten million times colder than deep space. The unprecedented level of control afforded by these systems, in which almost every parameter can be tuned at will, provides a valuable experimental arena in which to explore quantum collective behavior.

  4:15 pm Question & Answer
4:30 pm

Or Hen,
2015-2017 Fellow,
(Experimental Nuclear & Particle Physics)

Low Energy Tests of the Standard Model

The Standard Model of particle physics describes the universe using elementary particles and their fundamental interactions. In the last century, its predictions stood rigorous experimental tests with great success, leading to its definition as one of the greatest triumph of modern day physics. However, outstanding questions like the matter – anti-matter asymmetry, dark matter, dark energy and others, indicate that the standard model is still incomplete and new physics must be out there for us to find.

Searches for new physics beyond the standard model are therefore a main activity in particle physics. Low-energy β decay studies, in particular, offer the possibility of detecting deviations from Standard Model predictions of the weak interaction which signal new physics. These "low energy precision frontier" searches are complementary to the high-energy searches performed by the Large Hadron Collider at CERN and other high-energy/high-luminosity facilities.

In this talk, I will present the new MIT-led OLIVIA experiment, which will measure 8Li beta decay using a state-of-the-art Time-Projection Chamber.

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