Quantum Information Seminars

Topological stabilizer codes with a power law energy barrier via welding

Speaker: 
Kamil Michnicki, MIT
Event Date and Time: 
Thu, 2013-04-04 10:00 - 11:00
Location: 
Hennings 309B
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
A high energy barrier for logical errors in local stabilizer code Hamiltonians is essential for the development of self-correcting quantum memories. These devices would have an unbounded storage time as a function of the total number of qubits. We introduce a new primitive, called welding, for combining two stabilizer codes to produce a new stabilizer code for which the resulting shape of the logical operators is the combination of the former two shapes.

Quantum Control and Fault-tolerant quantum computing

Speaker: 
Gerardo Paz, UCL Los Angeles
Event Date and Time: 
Wed, 2013-03-27 14:30 - 15:30
Location: 
Hennings 309B
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
Quantum control (QC) and the methods of fault-tolerant quantum computing (FTQC) are two of the cornerstones on which the hope for a quantum computer rests. However QC methods do not generally scale well with the size of the system, and it is not known how their performance is hindered when integration with FTQC methods, especially considering these demand a large system size overhead, is attempted under realistic noise models.

Universal Uncertainty Relations

Speaker: 
Vlad Gheorghiu, Institute for Quantum Science and Technology at the Univ. of Calgary
Event Date and Time: 
Wed, 2013-03-06 14:30 - 15:30
Location: 
Hennings 309B
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
Uncertainty relations lie at the core of quantum mechanics and are a direct manifestation of the non-commutative structure of the theory. They impose intrinsic limitations on the precision with which physical properties can be simultaneously determined. The modern work on uncertainty relations employs \emph{entropic measures} to quantify the lack of knowledge associated with measuring non-commuting observables.

Optical continuous-variable cluster states as a collection of entangled spins

Speaker: 
Nicholas Menicucci, U Sydney, Australia
Event Date and Time: 
Wed, 2013-01-09 14:00 - 15:00
Location: 
Hennings 318
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
Measurement-based quantum computation uses local measurements on a highly entangled resource state, called a cluster state, to perform computation. Optical continuous-variable cluster states store quantum information in continuous degrees of freedom in modes of light. Using the Schwinger Representation of SU(2), which maps a pair of harmonic oscillators to a single quantum mechanical spin, we reinterpret a class of continuous-variable cluster states as a system of entangled spins. This identification allows us to apply known results for angular momentum to this seemingly unrelated system.

Concatenation Techniques for Quantum Error-Correcting Codes

Speaker: 
Markus Grassl, Centre for Quantum Technologies, Singapore
Event Date and Time: 
Tue, 2012-10-09 14:30 - 16:00
Location: 
Hennings 318
Intended Audience: 
Graduate
Quantum error-correcting codes (QECC) are important to build large scale quantum computers. The talk will discuss various concatenation techniques that allow to build large codes from smaller component codes. Moreover, it will be shown how concatenation techniques can be used to construct codes for particular channels, e.g. the amplitude damping channel.

`Measurement of Quantum Mechanical Operators' Revisited

Speaker: 
Leon Loveridge, UBC
Event Date and Time: 
Fri, 2012-09-28 14:00 - 15:00
Location: 
Hennings 318
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
In 1952 Wick, Wightman and Wigner argued that relativistic symmetry dictates the impossibility of measuring a relative phase factor in a superposition of bosonic and fermionic states. The ensuing reduction of the set of observables is called a superselection rule. I'll review some history and contrasting perspectives on the subject, other occurences of superselection rules, and various arguments in their favour.

Characterizing topological spin liquids with Projected Entangled Pair States

Speaker: 
Norbert Schuch, Universitaet Aachen, Germany
Event Date and Time: 
Tue, 2012-09-18 14:00 - 15:00
Location: 
Hennings 318
Local Contact: 
Robert Raussendorf
We apply the framework of Projected Entangled Pair States (PEPS) to characterize the spin liquid nature of resonating valence bond (RVB) states on the kagome lattice.

Quantum Architectures

Speaker: 
Paul Pham, U Washington
Event Date and Time: 
Fri, 2012-09-14 10:00 - 11:00
Location: 
Hennings 309B
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
Quantum architecture is the study of how efficiently a quantum algorithm can be implemented given realistic constraints on qubit layout and interactions. The usual model is a two dimensional lattice with single- and two-qubit nearest-neighbor gates.

Nanoscale optomechanics: sensors and hybrid quantum systems

Speaker: 
Paul Barclay, University of Calgary
Event Date and Time: 
Wed, 2012-09-12 15:00 - 16:00
Location: 
Hennings 309B
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
Recent advances in optomechanics utilize the co-localization of optical and mechanical modes for coherent energy exchange between photons and phonons within nanoscale structures. These optomechanical devices have demonstrated exceptional promise as sensors of mechanical motion, and as probes of mesoscopic quantum effects. In this talk I will review these advances, and discuss efforts to create optomechanical devices optimized for detecting torsional excitations associated with nanoelectronic and magnetic systems.

Equilibration and thermalization of quantum many-body systems: A quantum information perspective

Speaker: 
Jens Eisert, Freie Universitaet Berlin, Germany
Event Date and Time: 
Tue, 2012-09-11 14:00 - 15:00
Location: 
Hennings 309B
Local Contact: 
Robert Raussendorf
Intended Audience: 
Graduate
Complex quantum systems out of equilibrium are at the basis of a number of the most intriguing puzzles in physics. This talk will be concerned with recent progress on understanding how quantum many-body systems out of equilibrium eventually come to rest. The first part of the talk will highlight theoretical progress on this question, taking in several ways a quantum information view - employing ideas of Lieb-Robinson bounds, quantum central limit theorems and of concentration of measure.
Syndicate content
Website development by Checkmark Media. Designed by Armada.

a place of mind, The University of British Columbia

Faculty of Science
Department of Physics and Astronomy
6224 Agricultural Road
Vancouver, BC V6T 1Z1
Tel 604.822.3853
Fax 604.822.5324

Emergency Procedures | Accessibility | Contact UBC | © Copyright The University of British Columbia