Events

Anqi Huang - IQC

Quantum key distribution (QKD) is able to achieve information-theoretic security in principle. However, in practice, imperfect devices threaten the security of quantum cryptographic systems. As a promising countermeasure against practical attacks, measurement-device-independent (MDI) QKD is immune to all detector side-channel attacks. Nevertheless, there are some limitations of the MDI QKD protocol. To overcome the technical limitations of MDI QKD, I scrutinized and evaluated other two countermeasures against imperfect detections.

Thomas Aref, University of Illinois at Urbana-Champaign

My research focuses on probing superconducting quantum bits or qubits with acoustic radiation in the form of surface acoustic waves (SAWs). This allows the investigation of sound interacting with artificial atoms on a quantum mechanical level, i.e. quantum acoustics with traveling phonons. We can then reproduce findings from quantum optics with sound taking over the role of light, highlighting the similarities between phonons and photons.

Yiwen Chu - Yale University

The ability to engineer and manipulate different types of quantum mechanical objects allows us to take advantage of their unique properties and create useful hybrid technologies. Thus far, complex quantum states and exquisite quantum control have been demonstrated in systems ranging from trapped ions to superconducting resonators. Recently, there have been many efforts to extend these demonstrations to the motion of complex, macroscopic objects.

Sangil Kwon: Phase in Superfluids and Spontaneously Broken Gauge Symmetry

It is often said that superfluids (including superconductors) can be described by a macroscopic quantum wavefunction and their phase transition can be understood based on the concept of spontaneously broken gauge symmetry. This statement is not, however, trivial at all. In this seminar, I will discuss some conceptual problems that stem from applying the concept of spontaneously broken gauge symmetry to superfluids.

Anqi Huang, Quantum Hacking after Measurement-Device-Independent Quantum Cryptography

Supervisor: Christopher Wilson

Thesis is on display in the Engineering graduate office, DWE 3520C. Oral defence Monday, March 26, 12:30p.m., EIT 3142.

Gilles Brassard, Université de Montréal

It is generally believed that experimental violations of Bell's inequalities (especially the recent so-called loophole-free experiments) provide evidence that quantum theory cannot be both local and realistic. We demonstrate to the contrary that all reversible-dynamics no-signalling operational theories (including unitary quantum theory) can be given a local-realistic interpretation.

Stories of a Yale Professor turned Entrepreneur, turned Environmental Activist - what next?

Featured Speaker: Dr. Ron Dembo

Peter Zoller - University of Innsbruck

We start with an overview of chiral quantum optics as quantum light-atom interfaces with broken left- right symmetry and associated quantum optical phenomena and applications. While chiral quantum optics is traditionally discussed in context of nano-photonics and nano fibers , we propose here a novel ‘free-space’ chiral quantum optics realized as atoms in free space coupled to a ‘few-atom’ quantum antenna. In particular, we discuss free space photonic quantum links between atoms (qubits) equipped with sending and receiving quantum antennas.

Xiaodong Ma: Topological insulator and the quantum anomalous Hall effect

The quantum anomalous Hall effect (QAHE) is defined as a quantized Hall effect in a system without an external magnetic field. Its physical origin relies on the intrinsic topological inverted band structure and ferromagnetism.

Yoonseok Lee, University of Florida

After the discovery of topological insulators, the concept of topology permeated the various fields of condensed matter physics. Symmetry of a quantum system plays an intriguing role in close association with topology, expanding the range of topological quantum systems to superconductors/superfluids. Superfliuid 3He, which has been a prime example of symmetry breaking phase transition, is also recognized as a quantum system with various topological nature.