Seminar

Subscribe to Seminar
Monday, April 28, 2014 11:00 am - 12:00 pm EDT (GMT -04:00)

Stobinska: Quantum state engineering of multiphoton quantum superpositions

Magdalena Stobinska, University of Gdańsk/Polish Academy of Sciences, Warsaw

We discuss a device capable of filtering out two-mode states of light with mode populations differing by more than a certain threshold, while not revealing which mode is more populated. It would allow engineering of macroscopic quantum states of light in a way which is preserving specific superpositions. As a result, it would enhance optical phase estimation with these states. We propose an optical scheme, which is a relatively simple, albeit non-ideal, operational implementation of such a filter.

Monday, May 5, 2014 2:30 pm - 3:30 pm EDT (GMT -04:00)

Pappas: Quantum Information, Surfaces, and Interfaces

David P. Pappas, NIST

Progress in the field of experimental quantum information processing has been steady over the past decade with important developments continuing to be made in the understanding, design, and measurement of systems at the quantum level. As the boundaries of these measurements are pushed, we are finding that surface and interfacial properties play an increasingly important role. In general, this field has benefitted immensely from advances in VLSI.

Thursday, April 17, 2014 2:00 pm - 3:00 pm EDT (GMT -04:00)

Jafari-Salim: Superconducting Nanostructures for Quantum Detection of Electromagnetic Radiation

Amir Jafari-Salim, IQC

In this talk, I will give a summary of my recent research on superconducting nanostructures for quantum detection of electromagnetic radiation. In this regard, electrodynamics of topological excitations in 1D superconducting nanowires and 2D superconducting nanostrips is investigated. Topological excitations in superconducting nanowires and nanostrips lead to crucial deviation from the bulk properties.

Tuesday, April 22, 2014 11:00 am - 12:00 pm EDT (GMT -04:00)

Hilke: Graphene growth and characterization for device applications

Michael Hilke, McGill University

We will review several proof of principle applications for graphene based devices performed in our group, including in field sensors, electronics, THz spectroscopy, spintronics, nanofluidics, and even musical instruments. We will then discuss the synthesis mechanism of graphene as well as the synthesis of very large single layered graphene monocrystals with various shapes, ranging from hexagons to fractals, dubbed graphlocons.

Monday, April 28, 2014 2:30 pm - 3:30 pm EDT (GMT -04:00)

Raul Garcia-Patron: Ultimate communication capacity of quantum optical channels

Raul Garcia-Patron, Max-Planck-Institut für Quantenoptik

Optical channels, such as fibers or free-space links, are ubiquitous in today's telecommunication networks. A complete physical model of these channels must necessarily take quantum effects into account in order to determine their ultimate performances. Specifically, Gaussian bosonic quantum channels have been extensively studied over the past decades given their importance for practical purposes.

Thursday, April 17, 2014 12:00 pm - 1:00 pm EDT (GMT -04:00)

Kothari: Exponential improvement in precision for simulating sparse Hamiltonians

Robin Kothari

We provide a quantum algorithm for simulating the
dynamics of sparse Hamiltonians with complexity sublogarithmic in
the inverse error, an exponential improvement over previous methods.
Unlike previous approaches based on product formulas, the query
complexity is independent of the number of qubits acted on, and for
time-varying Hamiltonians, the gate complexity is logarithmic in the
norm of the derivative of the Hamiltonian. Our algorithm is based on
a significantly improved simulation of the continuous- and

Monday, April 21, 2014 1:00 pm - 1:00 pm EDT (GMT -04:00)

Imai: NMR as a low energy probe of condensed matter

Takashi Imai, McMaster University

NMR (Nuclear Magnetic Resonance) is a versatile probe of condensed matter, and has a broad range of applications in chemistry, medicine (MRI), oil industry, etc. NMR has become so popular outside the conventional realm of physics that the crucial role NMR has been playing in condensed matter physics is sometimes overlooked. I will explain how condensed matter physicists use NMR as a powerful low energy probe of solids, drawing examples from modern research into statistical physics, magnetism, and superconductivity.

Wednesday, April 9, 2014 10:30 am - 10:30 am EDT (GMT -04:00)

Scholz: Operationally-Motivated Uncertainty Relations for Joint Measurability and the Error-Disturbance Tradeoff

Volkher Scholz, Institute for Theoretical Physics ETH Zurich

We derive new Heisenberg-type uncertainty relations for both joint measurability and the error- disturbance tradeoff for arbitrary observables of finite-dimensional systems. The relations are formulated in terms of a directly operational quantity, namely the probability of distinguishing the actual operation of a device from its hypothetical ideal, by any possible testing procedure whatsoever.

Monday, April 7, 2014 1:00 pm - 1:00 pm EDT (GMT -04:00)

Hormozi: Topological Quantum Compiling with Fractional Quantum Hall States

Layla Hormozi, National University of Ireland

A topological quantum computer is a hypothetical device in which intrinsic fault-tolerance is embedded in the hardware of the quantum computer. It is envisioned that in these devices quantum information will be stored in certain topologically ordered states of matter and quantum computation will be carried out by braiding the world-lines of quasiparticle excitations that obey non-Abelian statistics, around one another, in specific patterns.

Tuesday, April 8, 2014 11:00 am - 11:00 am EDT (GMT -04:00)

Fan: Quantum receivers beyond the stand quantum limit of coherent optical communications

Jingyun Fan, National Institute of Standards and Technology

Measurements based on the quantum properties of physical system have enabled many tasks which are not possible by any classical means. In this talk, I introduce two quantum receivers that discriminate nonorthogonal optical coherent states unconditionally surpassing the standard quantum limit, with mean photon numbers ranging from single photon level to many photons, thus bridging the gap between quantum information technology and state-of-the art coherent communications.