Future graduate students

Fabrication of Diamond Based Fabry-Perot Cavities: Boring is beautiful

Madelaine Liddy, IQC

Nitrogen-vacancy (NV) centers in diamond are promising candidates for acting as the nodes in a quantum network. Previous work has demonstrated the entanglement between two NV centers over a distance of 1.3km for the loophole-free bell test in 2015.

Quantum Entanglement, Sum-of-Squares and the Log-Rank Conjecture

Pravesh Kothari, Princeton University

This talk will be about a sub-exponential time algorithm for the Best Separable State (BSS) problem. For every constant \eps>0, we give an exp(\sqrt(n) \poly log(n))-time algorithm for the 1 vs 1-\eps BSS problem of distinguishing, given an n^2 x n^2 matrix M corresponding to a quantum measurement, between the case that there is a separable (i.e., non-entangled) state \rho that M accepts with probability 1, and the case that every separable state is accepted with probability at most 1-\eps.

Harnessing quantum systems with long-range interactions

Zhexuan Gong, University of Maryland, College Park

A distinctive feature of atomic, molecular, and optical systems is that interactions between particles are often long-ranged. Together with control techniques from quantum optics, these long-range interacting systems could be harnessed to achieve faster quantum information processing and to simulate novel quantum many-body phenomena. A

Harnessing quantum entanglement 

Laura Mancinska, University of Bristol 

The phenomenon of entanglement is one the key features of quantum mechanics. It can be used to attain functionality lying beyond the reach of classical technologies. In practice, however, finding the best way of harnessing entanglement for a given task is extremely challenging and one is often forced to resort to ad hoc methods. The mathematical structure of entanglement- enabled strategies is poorly understood and many basic questions remain open. This lack of understanding has prevented us from fully exploiting the advantages that entanglement can offer for operational tasks.

Epitaxial Growth of Silicon Nanowires and Niobium Thin Films for Magnetic Resonance Force Microscopy

Michele Piscitelli

Magnetic Resonance Force Microscopy (MRFM) is an imaging technique enabling the acquisition of magnetic resonance images at nanometer scales. Single electron spin sensitivity has been demonstrated [1] and current MRFM research is focused on working towards achieving single nuclear spin sensitivity. In general, an MRFM setup requires a nano-scale source of high magnetic field gradients to modulate the sample spins and a cantilever-based detection scheme to measure their magnetic moment.

Robust quantum optimizer with full connectivity

Rakesh Tiwari, McGill University

Quantum phenomena have the potential to speed up the solution of hard optimization problems. For example quantum annealing, based on the quantum tunneling effect, has recently been shown to scale exponentially better with system size as compared with classical simulated annealing. However, current realizations of quantum annealers with superconducting qubits face two major challenges. First, the connectivity between the qubits is limited, excluding many optimization problems from a direct implementation.

Expected communication cost of distributed quantum tasks

Penghui Yao, University of Maryland, Baltimore

Data compression is a fundamental problem in quantum and classical information theory. A typical version of the problem is that the sender Alice receives a classical or quantum) state from some known ensemble and needs to transmit it to the receiver Bob with average error below some specified bound. We consider the case in which the message can have a variable length and goal is to minimise its expected length. For the classical case, this problem has a well-known solution given by the Huffman coding.

Quantum entanglement through the lens of computation and cryptography 

Henry Yuen, University of California at Berkeley

Quantum entanglement was once a philosophical peculiarity in physics — Einstein famously derided it as spooky action at a distance. Alongside wave/particle duality and the uncertainty principle, entanglement was just another bizarre feature of quantum mechanics. However, the study of quantum computation and quantum information has established entanglement as central to the story that connects quantum physics, computer science, and information theory.

Trapped-ion quantum logic with near-field microwave-driven gates

David Allcock, National Institute of Standards and Technology, Boulder

Hyperfine qubits in laser-cooled trapped atomic ions are one of the most promising platforms for general-purpose quantum computing. Magnetic field-insensitive ‘clock states’ and near-infinite lifetimes allow for minute-long memory coherence times as well as qubit frequencies that are in the convenient microwave domain [1]. Most work on these qubits has so far focussed on using lasers for gate operations, however there are several schemes that offer the prospect of performing all coherent operations using purely electronic methods [2,3].

Progress and challenges in designing a universal Majorana quantum computer

Torsten Karzig, Microsoft Research Station Q

I will discuss a promising design proposal for a scalable topological quantum computer. The qubits are envisioned to be encoded in aggregates of four or more Majorana zero modes, realized at the ends of topological superconducting wire segments that are assembled into superconducting islands with significant charging energy. Quantum information can be manipulated according to a measurement-only protocol, which is facilitated by tunable couplings between Majorana zero modes and nearby semiconductor quantum dots.