Upcoming Events

• CQT CS Talk by Kai-Min Chung, Academia Sinica, Taipei — 22 Feb, 02:00 PM

CQT CS Talk by Kai-Min Chung, Academia Sinica, Taipei
Title: General Randomness Amplification with Non-signaling Security
Date/Time: 22 Feb, 02:00 PM
Venue: CQT Level 3 Seminar Room, S15-03-15
Abstract:
Highly unpredictable events appear to be abundant in life. However, when modeled rigorously, their existence in nature is far from evident. In fact, the world can be deterministic yet at the same time the predictions of quantum mechanics are consistent with observations. Assuming that randomness does exist but only in a weak form, could highly random events be certifiably demonstrated?

In this talk, we resolve this question positively by constructing the first no-signaling secure device-independent randomness amplification protocol that works for arbitrary weak sources with sufficient entropy. Our result implies that the laws of physics either do not allow randomness or allow it in an almost perfect quality. The assumptions under which we derive our conclusion are minimal and in particular, do not rely on any structural or independence conditions assumed in previous works. If in addition quantum mechanics is assumed to be complete, our result implies that an unbounded amount of almost perfect randomness can be experimentally produced from a single source of weak randomness.

Joint work with Yaoyun Shi and Xiaodi Wu.

• CQT Talk by Dominic O’Brien, Networked Quantum Information Technologies, University of Oxford. — 28 Feb, 02:00 PM

CQT Talk by Dominic O’Brien, Networked Quantum Information Technologies, University of Oxford.
Title: The Networked Quantum Information Technologies (NQIT) Hub: Project overview and engineering challenges.
Date/Time: 28 Feb, 02:00 PM
Venue: CQT Level 3 Seminar Room, S15-03-15
Abstract: Quantum information processing is developing rapidly, with early stage engineering efforts developing worldwide. NQIT is a large UK government funded effort to develop and engineer a range of different quantum technologies for information processing. In this seminar an overview of the project will be given, together with details of a major demonstration focus of the programme, a photonically connected network of ion-traps. Engineering challenges and the approach being taken to address these will be presented.

• CQT Talk by Robert Mann, University of Waterloo — 02 Mar, 04:00 PM

CQT Talk by Robert Mann, University of Waterloo
Title: Noisy Quantum Cosmology
Date/Time: 02 Mar, 04:00 PM
Venue: CQT Level 3 Seminar Room, S15-03-15
Abstract:
Much effort has been devoted into understanding the quantum mechanical properties of gravitational interactions. I describe recent work exploring the suggestion that gravitational interactions are mediated by a fundamental classical channel, a project known as Classical Channel Gravity. I discussed the basic setup of this approach and then discuss possible ways of empirically constraining CCG using laboratory experiments. I will then
describe how CCG can be generalized to a curved spacetime setting. This model offers the possibility that some properties of our universe, modelled using a Friedman-Robertson-Walker metric, can emerge from CCG by introducing an underlying quantum system for the dynamical variables, avoiding well known difficulties in trying to quantize the spacetime itself. The quantum decoherence necessary in such a measurement model manifests itself as a dark energy fluid that fills the spacetime and whose equation of state asymptotically oscillates around the value $w=-1/3$, regardless of the spatial curvature, which provides the bound between accelerating and decelerating expanding FRW cosmologies.

• Quantum Thermodynamic Talk by Giulio Casati, Center for, Como-Italy Complex Systems — 03 Mar, 11:00 AM

Quantum Thermodynamic Talk by Giulio Casati, Center for, Como-Italy Complex Systems
Title: THAT KIND OF MOTION WE CALL HEAT - A major societal problem for the 21st century
Date/Time: 03 Mar, 11:00 AM
Venue: CQT Level 3 Seminar Room, S15-03-15
Abstract: Providing a sustainable supply of energy to the world’s population will become a major societal problem for the 21st century as fossil fuel supplies decrease and world demand and environmental concern increases. Thermoelectric phenomena, which involve the conversion between thermal and electrical energy, and provide a method for heating and cooling materials, are expected to play an increasingly important role in meeting the energy challenge of the future.
To this end it is important to understand the microscopic mechanism, classical and quantum, which determines the macroscopic laws of heat transport and allows to control the heat current.

• CQT Talk by Dajun Wang, The Chinese University of Hong Kong — 08 Mar, 11:00 AM

CQT Talk by Dajun Wang, The Chinese University of Hong Kong
Title: Collisions of ultracold polar molecules with controlled chemical reactivity
Date/Time: 08 Mar, 11:00 AM
Venue: CQT Level 3 Seminar Room, S15-03-15
Abstract: Ultracold polar molecules with fully controlled internal and external degrees of freedom have applications in diverse fields including ultracold chemistry, strongly correlated many-body physics, quantum information, etc. Recent experiments with two-body reactive molecules have confirmed that chemical reactions can still happen at ultracold temperatures with rates dominated by the quantum behavior of the collision partners. In this talk, I will report our recent results in creating and studying an optically trapped gas of ground-state ultracold bosonic NaRb molecules with fully controlled inelastic loss channels and chemical reactivity. We show that rapid loss of molecules persists, contrary to intuitive expectations, regardless of the two-body chemical reactivity. Our investigation also provides strong evidences that collision complexes are playing a key role in understanding the observed losses.

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