CQT Colloquium by Barry C. Sanders, University of Calgary

Title: PT Symmetry as a Time-Dependent Inner Product on Hilbert Space
Date/Time: 20-Aug, 11:00AM
Venue: Online via Zoom

Abstract: We show that PT Symmetry is explained within our framework of time-dependent Hilbert-space inner product, which we show is equivalent to quantum-channel evolution. Despite unobservability of inner product, we show that a changing inner product is discernible and include a qubit example, which we show is simulatable by unitary evolution of a qutrit. Furthermore, we prove that this changing inner product confers no advantage for quantum computing


Please register to receive zoom details: http://bit.ly/cqtwebinar    

CQT Online Talk by Chithrabhanu Perumangatt, CQT, NUS

Title: Linear and compact entangled photon source designs for quantum communication
Date/Time: 20-Aug, 04:00PM
Venue: Online Event

Abstract: As the field of quantum communication is getting matured enough to be applied for real-life solutions, peruse for high performing,compact and field deployable quantum sources have greater importance. One of the main focus of our group is to enable satellite based quantum networks, for which we have been developing different entangled photon sources that are stable and compact enough to be deployed in such environments.

In this talk, I will be describing three different sources which are developed from our group and their prospects for different applications.

 Please register to receive zoom details: http://bit.ly/cqtwebinar  

CQT Webinars Series on Quantum Computation and Quantum Simulation

Title: Dissipation induced non-stationary complex quantum dynamics 
Date/Time: 07-Aug, 04:00PM
Venue: Online via zoom

Abstract: The assumption that physical systems relax to a stationary 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 eigen state thermalization hypothesis. When an environment is present the expectation is that all of phase space is explored, eventually leading to stationarity. 
 
In this talk, we will identify and discuss simple and generic conditions for dissipation to prevent a quantum many-body system from ever reaching a stationary state [1]. We go beyond dissipative quantum state engineering approaches towards controllable long-time non-stationary dynamics typically associated with macroscopic complex systems. The resulting coherent and oscillatory evolution constitutes a dissipative version of a quantum time-crystal.
 
We will show how such dissipative dynamics can be engineered and studied with fermionic ultracold atoms in optical lattices using current technology. We discuss how dissipation leads to long-range quantum coherence, complexity, and η-pairing indicating a superfluid state in these setups [2] and the potential connection to driving induced superconductivity [3].
 
[1] B. Buca, J. Tindall, and D. Jaksch, Complex coherent quantum many-body dynamics through dissipation, Nature Communications 10, 1730 (2019)
[2] J. Tindall, B. Buca, J.R. Coulthard, D. Jaksch, Heating-Induced Long-Range η-Pairing in the Hubbard Model, Phys. Rev. Lett. 123, 030603 (2019).
[3] J. Tindall, F. Schlawin, M. Buzzi, D. Nicoletti, J.R. Coulthard, H. Gao, A. Cavalleri, M. Sentef and D. Jaksch, Dynamical Superconductivity in a Frustrated Many-Body System, preprint arXiv:2005.09073 (2020).

Speaker: Dieter Jaksch, University of Oxford and CQT, NUS, Singapore 

Organizer and Host: CQT Principal Investigator Dimitris G. Angelakis

Register: http://bit.ly/cqtonlinetalks