This is the fourth of the Intellectual Property (IP) Management Lunch and Learn Lecture Series. We are bringing in thought leaders in the protection and management of intellectual property, including many years of experience in relevant areas of information technology.
This session will be led by Jeffrey Wong.
Rigorous RG algorithms and area laws for low energy eigenstates in 1D
Thomas Vidick, California Institute of Technology
One of the central challenges in the study of quantum many-body systems is the complexity of simulating them on a classical computer. We give a new algorithm for finding low energy states for 1D systems, based on a rigorously justified RG type transformation.
Optical manipulation of polariton in semiconductor microstructures
Félix Marsault, French National Center for Scientific Research
Cavity polaritons are bosonic quasiparticles arising from the strong coupling between photons and excitons. They can massively occupy a single quantum state in the regime of polariton lasing , showing particular properties such as long coherence times , long range spatial coherence  and a linearly polarized emission [1,2,3]. Moreover, they possess strong excitonic nonlinearities and thus provide a new platform for elliptical photonic manipulation, with the demonstration of a polariton spin switch , polariton transistors  and the proposal of other proof-of-principle operations for elliptical integrated logic circuits .
Entropy measurement in quantum systems
Dr. Mohammad Ansari, Peter Grünberg Institute, and Jülich-Aachen Research Alliance Institute (JARA)
Entropy is an important information measure. A complete understanding of entropy flow will have applications in quantum thermodynamics and beyond; for example it may help to identify the sources of fidelity loss in quantum communications and methods to prevent or control them. Being nonlinear in density matrix, its evaluation for quantum systems requires simultaneous evolution of more-than-one density matrix.
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.
This is the third of the Intellectual Property (IP) Management Lunch and Learn Lecture Series. We are bringing in thought leaders in the protection and management of intellectual property, including many years of experience in relevant areas of information technology.
This session will be led by Neil Henderson.
Tip induced superconductivity at mesoscopic point contacts on topological semimetals
Leena Aggarwal, Indian Institute of Science Education and Research, Mohali
I will present the observation of a new phase of matter, tip-induced superconductivity (TISC), that emerges only under mesoscopic metallic point contacts on topologically non-trivial semimetals like a 3-D Dirac semimetal Cd3As2, and a Weyl semimetal, TaAs. From theoretical considerations, it is believed that such semimetals exist near topological phase boundaries.
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 . 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].
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.
The Power of Randomized and Quantum Computation
Shalev Ben-David, Massachusetts Institute of Technology
Randomized and quantum computing offer potential improvements over deterministic algorithms, and challenge our notion of what should be considered efficient computation. A fundamental question in complexity theory is to try to understand when these resources help; on which tasks do randomized or quantum algorithms outperform deterministic ones?
In this talk, I will describe some of my work investigating this question, primarily in the query complexity (blackbox) model.
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
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.