Seminar

Monday, March 10, 2014 2:30 pm - 3:30 pm EDT (GMT -04:00)

Solano: Quantum simulations as our quantum theatre

Enrique Solano, Universidad del País Vasco, Bilbao, Spain

I will introduce the field of quantum simulations from a wide
scientific perspective. Then, I will discuss the relevance of quantum
simulations for reproducing different aspects of quantum physics:
nonrelativistic and relativistic quantum dynamics, physical and unphysical
quantum operations, as well as strong and ultrastrong light-matter
interactions. Finally, I will give examples in the context of trapped-ion
and circuit QED technologies.

Wednesday, April 9, 2014 3:00 pm - 4:00 pm EDT (GMT -04:00)

Traub: Algorithms and Complexity for Quantum Computing

Joseph F. Traub, Columbia University

We introduce the notion of strong quantum speedup. To compute this
speedup one must know the classical computational complexity. What is it about the problems of quantum physics and quantum chemistry that enable us to get lower bounds on the classical complexity?

Gerd Leuchs, Max Planck Institute for the Science of Light

The coupling between light and a single atom is probably the most fundamental process in quantum optics. The best strategy for efficiently coupling light to a single atom in free space depends on the goal. If the goal is to maximally attenuate a laser beam, narrow-band on- resonance laser radiation is required as well as a wave front approaching the atom from a 2_ solid angle.

Monday, March 17, 2014 2:30 pm - 3:30 pm EDT (GMT -04:00)

Delsing: Interaction between propagating phonons and a superconducting qubit

Per Delsing, Chalmers University of Technology Sweden

We present a new type of mechanical quantum device, where propagating surface acoustic wave (SAW) phonons serve as carriers for quantum information. At the core of our device is a superconducting qubit, designed to couple to SAW waves in the underlying substrate through the piezoelectric effect. This type of coupling can be very strong, and in our case exceeds the coupling to any external electromagnetic mode.

Tuesday, March 11, 2014 2:30 pm - 3:30 pm EDT (GMT -04:00)

Pernice: Light force devices and non-classical optics on a chip

Wolfram Pernice, Karlsruhe Institute of Technology, Germany

Nanophotonic devices allow for realizing complex optical functionality that is otherwise difficult to achieve with free-space optical setups. While such circuits find a multitude of applications in telecommunication and optical signal processing, their tremendous potential for non-classical optics remains largely unexplored. I will present an integrated platform in which key challenges of integrated quantum optics are addressed by combining nanophotonic and superconducting nanowire devices with optomechanical resonators.

Taehyun Yoon, Columbia University

In the XENON dark matter search experiment, trace contamination of Xe by Kr contributes background events through the beta decay of radioactive Kr-85. To achieve the required sensitivity of the detector, the contamination must be reduced below the part per trillion (ppt) level and this level must be known precisely. We have developed an atom trap trace analysis (ATTA) device using standard atom cooling and trapping techniques to detect Kr below the ppt level.

Xiasong Ma, Yale University

The advantages of single photons make them not only the workhorse of testing the foundations of quantum physics against the classical interpretation of nature, but also suitable for various tasks in quantum information processing. In my talk, I will first present our long-distance quantum teleportation with active feed-forward in real time. This experiment uses both quantum and classical optical links over 143 km free space between the two Canary Islands of La Palma and Tenerife and is a major step towards quantum communication on a global scale.

Thursday, February 13, 2014 12:00 pm - 1:30 pm EST (GMT -05:00)

Yao: Applications of Information Theory in Direct Sum and Direct Product Problems

Penghui Yao (Centre for Quantum Technologies, Singapore)

A fundamental question in complexity theory is how much resource is
needed to solve k independent instances of a problem compared to the
resource required to solve one instance. Suppose solving one instance of
a problem with probability of correctness p, we require c units of some
resource in a given model of computation. A direct sum theorem states
that in order to compute k independent instances of a problem, it

Monday, February 3, 2014 1:00 pm - 2:00 pm EST (GMT -05:00)

Hertzberg: Non-Equilibrium Phonons in Nanostructures: From MHz to THz.

Jared B. Hertzberg, University of Maryland

Quantized vibrations of the lattice (phonons) are intrinsic to all of condensed- matter physics. Most experimental probes, however, treat the phonons in terms of thermal-equilibrium quantities such as heat capacity and thermal conductance, rather than directly addressing the vibrational quanta. I will discuss two types of experiments employing nanofabricated devices and low-temperature techniques to explore and exploit non-equilibrium phonon behavior.