# Photonic Enhancement of Quantum Dot Molecules: Implications for Quantum Information

Tuesday, November 26, 2013 - 3:15pm - 4:30pm

Regents 109

Patrick Vora, National Research Council Postdoctoral Associate

United States Naval Research Laboratory

The development of a practical quantum bit, or qubit, remains one of the most important goals of quantum information science. The principle requirements for a qubit are the ability to 1) faithfully initialize the quantum state, 2) manipulate that state, and 3) readout the fiEnal state. When hosted in a semiconductor quantum dot molecule (QDM) (two quantum dots separated by a thin tunnel barrier), a pair of electron spins is a particularly promising qubit candidate. The T1 and T2 times in this system are impressive (milliseconds and microseconds, respectively), and optical pulses can be utilized to manipulate the spin on picosecond timescales. Successfully meeting the above requirements is a necessary, but not sufficient, step towards the eventual construction of a quantum computer. The true power of the qubit is only realized by entangling a large number of qubits together, a quantum network. A key advantage of semiconductor QDM-based qubits is their natural integration with both photonic and electronic circuits. This immediately suggests the tantalizing possibility of constructing a quantum network mediated by photons. Such a network could be hosted within a two-dimensional photonic crystal slab, where cavities and waveguides are readily patterned. In this seminar I will first provide an overview of QDMs and two-dimensional photonic crystals, focusing on the essential physics of each system as well as the interactions between them. I will then discuss some of our group’s recent results on a coupled QDM-cavity system including Purcell enhancement and cavity-assisted Raman scattering, the latter of which has important implications for a photon-mediated quantum network.

**REFRESHMENTS AT 3:00 PM IN REGENTS HALL 109**

**Host**: Edward Van Keuren**Discussion Leader**: Edward Van Keuren