Physics and Astronomy Ph.D. Thesis Defense - Peter Johnson - Dartmouth College

Title: "Aspects of Part vs Whole Relationship in Quantum Information Processing"

October 4, 2016
4 pm - 6 pm
Location
Steele 007
Sponsored by
Physics & Astronomy Department
Audience
Public
More information
Tressena Manning
603-646-2854

Abstract:

Over the past century, the phenomenon of quantum entanglement has evolved from Einstein's enigmatic "spooky action at a distance" to a crucial resource for quantum computing. Recent technological advances geared towards controlling quantum systems and harnessing quantum entanglement have borne new perspectives and challenges. One major challenge is the development of a theory of multi-partite entanglement. Quantum theory places highly non-trivial constraints on how entanglement may be distributed among the parts of a whole quantum system. In the simplest example, the more entangled system A is with system B, the less entangled system B can be with system C. This principle, known as the monogamy of entanglement, is a uniquely quantum feature enabling secure quantum key distribution protocols and having ramifications for control of many-body quantum systems.

In the first part of the talk, I describe our contributions toward understanding the principles governing the distribution of entanglement in multi-partite systems. In particular, we elucidate surprising connections between these kinematic constraints and the dynamical constraints of the “no-cloning” principle and the uncertainty principle for incompatible quantum observables.

In the second part of the talk, I describe our contributions towards developing methods to create and control many-body entanglement. Due to a number of recent experimental realizations, dissipative control of quantum systems is garnering increasing attention, alongside traditional unitary approaches. We investigate the use of dissipative control for driving a quantum system towards a target entangled state independently of initialization, a task known as “stabilization” -- subject to the realistic constraint that control resources be "quasi-local". In particular, we develop mathematical tools for discovering hidden structures among the parts of a multi-partite entangled state which enable their stabilization.

Location
Steele 007
Sponsored by
Physics & Astronomy Department
Audience
Public
More information
Tressena Manning
603-646-2854