Theoretical Physics

Search site


Physics & Astronomy
Latest News

New paper in Physical Review Letters

11 October 2016

"Power-Law Entanglement Spectrum in Many-Body Localized Phases", Maksym Serbyn, Alexios A. Michailidis, Dmitry A. Abanin, and Z. Papic, Phys. Rev. Lett. 117, 160601 (2016).

Efficiently simulating many-body localisation

The amount of quantum entanglement in a many-body wave function determines whether it can be efficiently compressed and encoded by a small number of classical parameters. Ground states of many-body systems are known to have low entanglement, and can be efficiently simulated by the so-called "matrix product states" -- the property which underlies the success of the density-matrix renormalisation group.

In a new paper published in Phys. Rev. Lett., the authors characterise the entanglement of highly excited states in many-body localised (MBL) systems by studying its "entanglement spectrum". MBL phases have been a subject of much recent interest as phases of matter that break ergodicity and thus avoid thermalisation. The paper argues that the entanglement structure of MBL states, while different from ground states, still allows for compact parametrisation by matrix product states. An efficient algorithm is developed to obtain highly excited states of large MBL systems. This work opens a door for studying a broad class of disordered quantum systems, inaccessible by other techniques. It is expected that the new algorithm will also give a much-needed insight into the nature of the transition between MBL and ergodic (thermal) phases.

journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.160601




Royal Society Meeting: Breakdown of Ergodicity in Quantum Systems

15 September 2016

Scientific discussion meeting organised by Professor Sir Michael Pepper FRS, Dr Arijeet Pal, Dr Zlatko Papic, Dr Ulrich Schneider and Professor Steven Simon

Ergodic systems lie at the heart of statistical physics since they reach thermal equilibrium and 'forget' their initial conditions, thereby allowing for coarse-grained classical descriptions. Recently, non-ergodic quantum many-body systems, which fail to thermalise and decohere completely, came into focus. This interdisciplinary meeting will address their fundamental challenges and experimental realisations, including many-body localisation and other novel, non-classical long-time behaviour. 

 

Register here




Sarah Harris published paper in Nature Communications

19 May 2016

Dr Sarah Harris who leads the Computational Biophysics group has published a paper entitled "Structural diversity of supercoiled DNA" in Nature Communications.

The article's reference is:

Rossitza N. Irobalieva, Jonathan M. Fogg, Daniel J.Catanese Jr, Thana Sutthibutpong, Muyuan Chen, Anna K. Barker, Steven J. Ludtke, Sarah A. Harris, Michael F. Schmid,    Wah Chiu & Lynn Zechiedrich. Nature Communications 6, Article number: 8440

It can be accessed here




20th Symposium on Topological Quantum Information, Athens (May 25-27, 2016)

28 April 2016

The series of Symposia on Topological Quantum Information aims at bringing together researchers interested in understanding topological phases, how they emerge in physical systems, and their potential for facilitating quantum computation.

Information and registration




Quantum Matter Out of Equilibrium Symposium taking place soon!

31 March 2016

4th-5th April

This series of symposia take place every few months and typically last for two days. Their purpose is to bring together young scientists (mainly PhD students and Postdocs) interested on topological quantum information promote their recent work and inspire collaborations.

To register please email you name and institution to topo-symp@leeds.ac.uk with 'Registration' as the subject heading.

Please see below for the schedule the day will follow:

Monday


09:30-12:30 Juan Garrahan: Aspects of slow relaxation, glasses and non-equilibrium.
12:30-13:30 Lunch
13:30-14:30 Henning Schomerus: Signatures of chaotic scattering from Majorana zero modes.
14:30-15:30 Earl Campbell: Cellular automata decoders on the toric code.
15:30-16:00 Break
16:00-17:00 Marta P Estarellas: Topologically protected localised states in spin chains.
17:00-17:30 Konstantinos Meichanetzidis: Topological edge states are monogamous.
17:30-19:00 Poster and Discussion Session


Tuesday


09:30-12:30 Andrew Green: Combining eld theory and tensor networks.
12:30-13:30 Lunch
13:30-14:30 Aires Ferreira: Robustness of topological phases in adatom-decorated graphene.
14:30-15:30 James Wootton: Quantum computing with parafermions.
15:30-16:00 Break
16:00-17:00 Adam Stokes: Decomposition of Hilbert Spaces and the second law of thermodynamics
17:00-17:30 Chris Self: Ising anyons at nite temperature.




Displaying results 11 to 15 out of 49