CTAMOP’s PhD student Jessica Barr, working within the Quantum Technology group with Alessandro and Mauro on topics of machine learning for quantum through the Leverhulme Trust Doctoral Programme LINAS, was part of the team winning the Best Teamwork Award at the Cyber 9/12 Strategy Challenge competition hosted by the Geneva Centre for Security Policy.
The piece, co-authored by CTAMOP member and Head of School, Prof. Mauro Paternostro, centres on the fundamental concept of entropy. Despite having been defined and explored as early as the mid 19th Century, no “unifying theory of entropy production valid for general processes, both classical and quantum, has … yet been formulated.”
Fellowship of the Young Academy of Europe for Dermot Green
CTAMOP member Dermot Green has been appointed as a fellow of the Young Academy of Europe.
The Young Academy of Europe (YAE) is a pan-European initiative of outstanding young scientists for networking, advocacy, scientific exchange, and science policy. The YAE is organised as a bottom-up initiative of a dynamic and innovative group of recognised European young scientists and scholars with outspoken views about science and science policy.
Dermot has been recognised for his outstanding leadership in the field of many-body theory for anti-matter interactions with atoms and molecules, but also for his roles in the international scientific community: He is a member of the International Scientific Advisory Board for the International Workshop for Positron and Positronium Physics (the flagship subject-specific conference in the field), Treasurer of the Institute of Physics Ireland and Secretary of the Institute of Physics Atomic and Molecular Interactions Group.
A paper by CTAMOP PhD student Pierpaolo Sgroi and Head of School Prof. Mauro Paternostro has been selected to adorn the front cover of Physical Review Letters.
The letter reports on a new scheme for reducing entropy production in a quantum system, and features not only the scientific prowess of its authors, but also the artistic flair of Prof Paternostro, whose 007 inspired diagram graces front cover of the journal.
Congratulations to Pierpaolo, Mauro and their Co-author G. Massimo Palma from UNIPA (Palermo) on this distinction.
The School announces the sad loss of Emeritus Professor Derrick Crothers MRIA, FAPS, FInstP, FIMA, FIET, CMath, CPhys, CEng, who passed away peacefully on 15 January 2021.
Prof. Crothers, who retired from Queen’s in 2007, spent most of his academic life in the School of Mathematics and Physics, and was inducted into the Royal Irish Academy in 1991. He made important contributions, disseminated in more than 300 publications, to theoretical atomic and molecular physics. His mathematical abilities were legendary, as was his love for rugby.
The School has sent a condolence note.
Due to the current COVID restrictions, the funeral will be arranged in strict private form.
Wednesday 9 December 4pm Location: MS Teams Speaker: Dr Berislav Buca (Clarendon Lab, University of Oxford)
The assumption that quantum systems relax to a stationary (time-independent) state in the long-time limit underpins statistical physics and much of our intuitive understanding of scientific phenomena. For isolated systems this follows from the eigenstate thermalization hypothesis. When an environment is present the expectation is that all of phase space is explored, eventually leading to stationarity. However, real-world phenomena, from life to weather patterns are persistently non-stationary. I will discuss simple algebraic conditions that prevent a quantum many-body system from ever reaching a stationary state, not even a non-equilibrium one. I call these algebraic conditions dynamical symmetries. This unusual state of matter, characterized by persistent oscillations, has been recently called a time crystal. I show that its existence can be even, counter-intuitively, induced through the dissipation itself. I give several physically relevant examples in both closed and open quantum many-body systems, including an isolated XXZ spin chain that for which the frequency of the persistent oscillations is fractal function of the interaction strength, a quasi-1D magnet with attractor-like dynamics, a spin-dephased Fermi-Hubbard model, and a two-component BEC in a lossy optical cavity which was recently experimentally studied. Finally, I briefly discuss ongoing work about emergence of discrete time translation symmetry in a random collision model.
References: B Buca, J Tindall, D Jaksch. Nat. Comms. 10 (1), 1730 (2019) M Medenjak, B Buca, D Jaksch. arXiv:1905.08266 (2019) B Buca, D Jaksch. Phys. Rev. Lett. 123, 260401 (2019) J Tindall, B Buca, J R Coulthard, D Jaksch. Phys. Rev. Lett. 123, 030603 (2019) J Tindall, C Sanchez Munoz, B Buca, D Jaksch. New J. Phys. 22 013026 (2020) C Booker, B Buca, D Jaksch. arXiv:2005.05062 (2020) B Buca et al. arXiv:2008.11166 (2020) Dogra, et al. Science, 366, 1496 (2019)
Seminar: Bayesian inference for quantum sensors and open quantum systems
Wednesday 25 November 4pm Location: MS Teams Speaker: Dr Ricardo Puebla, CTAMOP, Queen’s University Belfast
Inference techniques built on the Bayes’ theorem provide powerful tools for hypothesis testing and/or parameter estimation. In spite of other inference techniques, Bayesian inference deals with a probabilistic description of the key quantities to be determined. This is done by updating any prior information or knowledge according to the likelihood between the given set of observations and the proposed model to explain them. Such Bayesian techniques are routinely employed in many branches of science, and have been proven very useful in situations with a reduced number of observations and/or complex underlying models.
In this seminar I will review the main ingredients of Bayesian analysis and how to apply these techniques to quantum mechanical systems. In particular, I will discuss two illustrative and practical examples to showcase the suitability of Bayesian inference in quantum systems, namely, (i) an atomic-size quantum sensor aiming at detecting electromagnetic fields, and (ii) the inference of the environment properties of an open quantum system.
We are a Research Cluster of the School of Mathematics and Physics at Queen’s University Belfast in Northern Ireland. Our research interests are focused primarily on computational and theoretical physics.
The Old Physics Building, where
CTAMOP is situated.
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