Lectures on classical simulation of quantum computations – Richard Jozsa

From next week Professor Richard Jozsa (from Cambridge) will be visiting UTS to do some work with our group. He will also be giving a couple of lectures on the classical simulation of quantum computations. Richard is without question one of the world’s authorities on this subject, and an excellent speaker. So, if you get the chance to come along you definitely should!
Details below.Lectures on classical simulation of quantum computations

Lecturer: Professor Richard Jozsa, DAMTP, University of Cambridge UK.

Dates: Lecture 1, 4 April 2016; Lecture 2, 6 April 2016 (see detailed information below)

Lecture 1. Theory of Clifford operations.

Venue: CB10.03.460 (Room 460, Level 3, UTS City Campus Building 10), 235 Jones Street, Ultimo, NSW 2007
Time: 2-5PM (3-3:30PM: Tea break; 4:30-5PM: Free discussions)

Date: Monday, 4 April 2016

Introduction to Pauli and Clifford operations for qudits; construction of the metaplectic representation and the discrete Wigner function; a hidden variable model for Clifford circuits; implications for classical simulability.

Based mainly on ingredients from:

D. Gross  arXiv:quant-ph/0702004
V. Veitch, C. Ferrie, D. Gross, J. Emerson  arXiv:1201.1256

R. Jozsa, M. Van den Nest  arXiv:1305.6190

Lecture 2. Theory of matchgate (MG) computations.

Venue: CB02.04.010 (Room 10, Level 4, UTS City Campus Building 2), 15 Broadway, Broadway, NSW 2007

Time: 2-5PM (3-3:30PM: Tea break; 4:30-5PM: Free discussions)

Date: Wednesday, 6 April 2016

Introduction to MGs and relation to fermionic modes; MGs and partition functions for some solvable classical spin models; classical simulability of MG circuits with arbitrary input product states, intermediate measurements and adaptive choices of subsequent gates, and multi-line outputs, all being included simultaneously (D. Brod 2016). Further issues if time permits.

Based mainly on ingredients from:

B. Terhal, D. DiVincenzo  arXiv:quant-ph/0108010
D. Brod  arXiv:1602.03539
R. Jozsa, A. Miyake  arXiv:0804.4050
R. Jozsa, A. Miyake, S. Strelchuk  arXiv:1311.3046

Seminar announcement: Youming Qiao

Title: Quantum matching problems

Speaker: Youming Qiao, UTS

Time/Location: 2-3pm, 16 March 2016 (Wed) / CB10.02.410, UTS

Abstract: We describe two algorithmic problems, both of which can be viewed as quantum analogues of the perfect matching problem on bipartite graphs. Given several square matrices, we are asked to:
(1) decide if there is a full-rank matrix in the linear span of them;
(2) decide if there is a shrunk subspace. That is a subspace U, s.t. the union of the images under these matrices is of smaller dimension than U.

The first problem is the well-known polynomial identity testing problem, for which a deterministic efficient solution implies a strong arithmetic circuit lower bound. The second problem has a rich history and has appeared in various forms in a remarkable number of mathematical and computational areas. For example, it is a key problem in the theory of arithmetic circuits with divisions, as recently studied by Hrubeš and Wigderson. After introducing these problems, we will present a couple of ingredients in a recent deterministic efficient algorithm for the second problem. These include a polynomial degree upper bound on generating the ring of matrix semi-invariants, and a linear algebraic analogue of the augmenting path technique.

Based on joint works with Gábor Ivanyos and K. V. Subrahmanyam, arXiv:1508.00690 and arXiv:1512.03531. Another recent paper on this topic is arxiv:1511.03730.

Seminar announcement: Mingsheng Ying

Title: Toward Automatic Verification of Quantum Programs
Speaker: Mingsheng Ying, UTS
Time/Location: 2-3pm, 9 March 2016 (Wed) / CB11.06.408, FEIT Seminar Room
Programming is error-prone. It is even worse when programming a quantum computer or designing quantum communication protocols, because human intuition is much better adapted to the classical world than to the quantum world? How can we build automatic tools for verifying correctness of quantum programs and quantum communication protocols? A logic for verification of both partial correctness and total correctness of quantum programs was developed in our paper [TOPLAS’2011, art. no. 19]. The (relative) completeness of this logic was proved. Recently, a theorem prover for automatic verification of partial correctness of quantum programs was built based on our logic [arXiv: 1601.03835]. To further develop automatic tools for verifying total correctness of quantum programs, we are working on techniques for synthesis of ranking functions that guarantee termination of quantum programs.
1. Partial correctness: for any input satisfying the precondition, if the program terminates, then the output satisfies the postcondition.
2. Total correctness: for any input satisfying the precondition, the program terminates and the output satisfies the postcondition.

TQC 2016: Berlin, 27-29 September

Forwarded from the organizers:


The 11th Conference on the Theory of Quantum Computation, Communication, and Cryptography – TQC 2016

Freie Universität Berlin

Berlin, Germany

27-29 September 2016


This is the eleventh in a series of conferences that aims to bring together the leading researchers in the areas of quantum computation, quantum communication and quantum cryptography. TQC covers all theoretical aspects of quantum information and submissions on these topics are solicited.

Areas of interest include, but are not restricted to:

* quantum algorithms

* models of quantum computation

* quantum complexity theory

* simulation of quantum systems

* quantum cryptography

* quantum communication

* quantum estimation and measurement

* intersection of quantum information and condensed-matter theory

* quantum coding theory

* fault-tolerant quantum computing

* entanglement theory

Important dates:

* Paper/Talk/Early-Poster submission deadline:  May 16, 2016

* Decision notification:  July 5, 2016

* Final manuscript deadline:  July 23, 2016

* Late-Poster submission deadline:  August 17, 2016

* Conference:  27-29 September, 2016

Two tracks: Conference(talk + proceedings) and Workshop(talk only). As the goal of TQC is to bring together researchers on all aspects of quantum information, submissions are solicited for two tracks:

* Conference (talk + proceedings): Submissions to this track must be original papers that have not previously appeared in published form. Accepted papers will be presented orally at the conference and will appear in the conference proceedings. The proceedings will be published by the OpenAccess LIPIcs (Leibniz International Proceedings in Informatics).

* Workshop(talk only): We solicit submissions for talk-only papers; accepted submissions will be presented orally at the conference but will not appear in the proceedings. This track allows authors to publish their work elsewhere and accepts already published material.

Programme committee:

* Gorjan Alagic

* Gilles Brassard

* Anne Broadbent (chair)

* André Chailloux

* Giulio Chiribella

* Frédéric Dupuis

* Joseph Fitzsimons

* Steve Flammia

* Sevag Gharibian

* Stacey Jeffery

* Elham Kashefi

* Iordanis Kerenidis

* Xiongfeng Ma

* Laura Mancinska

* Carl Miller

* Mio Murao

* Marco Piani

* Christopher Portmann

* Robert Raussendorf

* Christian Schaffner

* Norbert Schuch

* Peter Selinger

* Jamie Sikora

* Barbara Terhal

* Mark Wilde

Local organising committee (FU Berlin):

* Jens Eisert – chair

* Oliver Buerschaper – co-chair

* Juan Bermejo-Vega

* Dominik Hangleiter

* Albert Werner

* Carolin Wille

* and the entire QMIO group at the FU Berlin

Steering committee:

* Wim van Dam (UCSB)

* Aram Harrow (MIT)

* Yasuhito Kawano (NTT, Tokyo)

* Michele Mosca (IQC, Waterloo and Perimeter Institute)

* Martin Roetteler (Microsoft Research)

* Simone Severini (UCL)

* Vlatko Vedral (Oxford and CQT, Singapore)


For further information, please see http://tqc2016.physik.fu-berlin.de/

My talk at the Workshop on the Frontiers of Quantum Information and Computer Science

Back in September 2015 I was invited to present a seminar at the Workshop on Quantum Information and Computer Science, hosted by the Joint Centre for Quantum Information and Computer Science at the University of Maryland. (Video above and slides are here.)

My talk was on a recent paper that I wrote together with Ashley Montanaro and Dan Shepherd where we generalized the Boson Sampling argument of Aaronson and Arkhipov to spin systems. We argued that IQP Sampling, the process of sampling from IQP (Instantaneous Quantum Polytime) circuits, can not be efficiently simulated on classical computers to within a constant variation distance assuming a couple of plausible complexity theoretic conjectures.

Why is this interesting? Our argument demonstrates that the dynamics of randomly chosen Ising models can not be classically simulated – so we have identified one of the simplest physical systems that demonstrates so-called quantum supremacy.