Quantum Symposium 2015 - Program

Tentative Program

26 March, Thurs Venue: University Hall Auditorium, Level 2, University Hall, Lee Kong Chian Wing, NUS
09:30 Opening and Welcome address
09:40 Tim Spiller, The University of York, UK
Overview of the EPSRC Quantum Communication Hub
Arrow Abstract

The Quantum Communications Hub is a collaboration between eight UK universities and a spectrum of industrial partners. Our aim is to develop new quantum communications technologies that will reach new markets and enable widespread use and adoption. This talk gives an overview of the vision, the approach and the delivery of the Hub.

10:10 Coffee/Tea Break
10:30 Ian Walmsley, University of Oxford, UK
Networked Quantum Information Technologies
Arrow Abstract

The internet is powered by processing signals in solid-state electronics and transmitting them using guided-wave optics. The impact of this architecture illustrates why hybrid light-matter networks are a paradigm for effective distribution and processing of information. Quantum networks inherit the resilience, reliability and robustness of classical networks, and add the enhanced capabilities for communications, simulation and computation that quantum mechanics provides.
I will discuss the development of the network-based quantum computational engine that is the goal of the EPSRC NQIT Hub. These include processing nodes using trapped ions and superconducting quantum circuits to enable quantum logic operations, quantum memories to enable repeaters and controlled single-spins to enable quantum sensors. The nodes will be connected using a photonic network, thereby enabling efficient distribution and utilisation of entanglement across multiple nodes.

11:00 John Morton, University College London, UK
Donor Spin Qubits in Silicon Devices
Arrow Abstract

Electron and nuclear spins of donors in silicon are exceptional candidates for representing quantum bits, with coherence times of up to 3 seconds for the electron spin [1], up to 3 minutes for the neutral donor nuclear spin [2], and 3 hours for the ionized donor nuclear spin [3]. Furthermore, single-shot readout of both the electron spin and nuclear spin have been demonstrated, with measurement fidelities of up to 99.8% [4]. I will first discuss how the Stark shift caused by DC electric fields can be a powerful control method to locally tune different donor spins in- and out- of resonance, and to coherently drive Z-rotations [5]. I will then show how optically-driven donor-bound exciton transitions can be used to electrically detect of the donor electron spin resonance and discuss how this could provide a fruitful route to single-spin measurement at higher temperatures, lower magnetic fields, and using more simple nanodevice structures [6]. Finally, I will examine strategies for scaling up to arrays of multiple coupled dopant spins qubits.

[1] G. Wolfowicz et al., Nature Nanotechnology 8 561 (2013)
[2] M. Stege et al., Science 336 6086 (2012)
[3] K Saeedi et al., Science 342 830 (2013)
[4] J.J. Pla et al., Nature 489 541 (2012); Nature 496 334 (2013)
[5] G. Wolfowicz et al., Phys Rev Lett 113 157601 (2014)
[6] C. C. Lo et al., arXiv:1411.1324 (2014)

11:30 Christian Kurtsiefer, CQT, NUS
Connecting Photons and Atoms
Arrow Abstract

Many visions on quantum information processing networks rely assume interconnects between various physical systems. However, well-understood photonic systems like entangled photon sources, and well-understood localized implementations like atoms or ions have typically not compatible wavelengts and optical bandwidths.

In this presentation, I review our entangled photon pair source based on four wave mixing in an atomic vapour with photons that are compatible with atomic transitions. With this, we demonstrate a Hong-Ou-Mandel interference, and outline our method in temporal pulse shaping and increasing interaction efficiency in a unusual optical cavity geometry.

12:00 Lunch
14:00 Steve Beaumont, University of Glasgow, UK
The QUANTIC Quantum Enhanced Imaging Hub
Arrow Abstract

QUANTIC is a £29M investment by the UK Government to stimulate research and innovation in quantum enhanced imaging. Building on a £60M portfolio of research into the science of quantum enhanced imaging, QUANTIC will work with an initial consortium of 40 companies to translate laboratory demonstrators into new imaging modalities in new and existing products. This presentation will describe the QUANTIC structure, its vision and mission, explain its mechanism for promoting industrial innovation and describe its four major workpackages in imaging with correlation, with squeezing and with timing, and its work on the development of enabling devices (sources and detectors) which underpin the other workpackages and provide opportunities for commercialisation.

14:30 Alexander Ling CQT, NUS
Entangled Photons in Space - Lessons and Roadmap
Arrow Abstract

The Centre for Quantum Technologies has in place a program to integrate compact entangled photon systems with emerging nanosatellite technology, to enable cost-effective quantum optical experiments in space.
In the last few years, researchers at CQT have succeeded in building very compact and efficient photon-pair systems that are at a high technology readiness level, with many critical components that have been space-qualified. Full system tests have been successfully performed to demonstrate that the systems will survive launch and orbital conditions. Preliminary in-orbit results are expected in early 2016 or earlier.

15:00 Coffee/Tea Break & Discussions

27 March, Fri Venue: CQT Level 3 Seminar Room, S15-03-15, Science Drive 2, NUS
10:00 Mete Atature, University of Cambridge, UK
Quantum Optics with Solid-State Spins and Photons
Arrow Abstract

Spins confined in solids, such as quantum dots and atomic impurities provide interesting and rich physical systems. Their inherently mesoscopic nature leads to a multitude of interesting interaction mechanisms of confined spins with the solid state environment of spins, charges, vibrations and light. Implementing a high level of control on these constituents and their interactions with each other creates exciting opportunities for realizing stationary and flying qubits within the context of spin-based quantum information science. I will provide a snapshot of the progress and challenges for optically interconnected spins, as well as first steps towards hybrid distributed quantum networks.

10:30 Hugo Cable, University of Bristol, UK
Photonic Quantum Technologies
Arrow Abstract

Widely-anticipated future quantum technologies include large-scale secure networks, enhanced measurement and sensing, quantum simulators, and quantum-information processors, which promise exponentially-greater computational power for particular tasks. Photonics is destined to have a central role in such technologies owing to the high-speed transmission, outstanding low-noise properties of photons, and routine demonstration of high-visibility quantum interference. I will give an overview of the current activities at the Centre of Quantum Photonics, on the fundamental science and quantum engineering that will transition photonic quantum technologies from proof-of-principle demonstrations to real-world devices.

11:00 Coffee/Tea Break
11:30 Edward A Hinds, Imperial College, London, UK
Coupling Single Individual Dye Molecules to Optical Waveguides and Cavities
Arrow Abstract

We are developing the use of individual molecules coupled to optical waveguides and cavities as a way to produce photons for quantum information processing and as a nonlinearity able to couple photons to each other. In particular, we are investigating the dibenzoterrylene (DBT) molecule in a host matrix of crystalline anthracene. When cooled to a low temperature these molecules emit with high (34%) efficiency on the zero- phonon line, and with lifetime-limited line width. They are exceptionally photo-stable, and their optical dipole moments align naturally with the anthracene crystal. Hwang and Hinds [1] have discussed the exchange of radiation between the molecular dipole and an optical structure, and have shown that the radiative coupling to an integrated optical waveguide can be very efficient. We can now make single anthracene crystals of high optical quality, suitable for insertion into photonic devices, and can dope the crystals to achieve any desired density of DBT polarised molecules. I will report on this advance, and on our progress towards coupling these molecules to optical waveguides and cavities. [1] J. Hwang and E. A. Hinds, New J. Phys. 13 (2011).

12:00 Rainer Dumke, CQT, NUS
Superconducting and Cryogenic Atom Chips
Arrow Abstract

Recently superconducting atom chips have generated a lot of interest due to their attractive properties, such as the Meissner effect for type-I superconductors and vortices for type-II superconductors. Thermal and technical noise in proximity to superconducting surfaces have been shown both theoretically and experimentally to be significantly reduced compared to conventional atom chips. Superconducting atom chips have the potential to coherently interface atomic and molecular quantum systems with quantum solid state devices. I will present recent developments in our superconducting atom chip experiment. Trapping ultra cold atoms with vorticies induced in a type II superconducting micro structure and electric field measurements originating from absorbates on a cryogenic atomchip

12:30 Lunch
14:00 Peter Kruger, The University of Nottingham, UK
Turning Sensitive Atomic Probes into Devices - The UK Quantum Technologies Hub for Sensors and Metrology
Arrow Abstract

Harnessing quantum systems based on cold atoms, ions and quantum gases has facilitated the development of novel sensing and metrology schemes. Already today the most accurate measurements of the gravitational acceleration and the best magnetometers and clocks are based on atomic quantum systems. Many schemes in these and other domains, such as rotation sensors for navigation, are rapidly improving in their performance, and new methods are being invented. As part of the UK's recent initiative on promoting this type of development in quantum technologies, we have formed a Hub on Quantum Sensors and Metrology between the UK Universities of Birmingham, Nottingham, Glasgow, Southampton, Strathclyde, and Sussex. The Hub's goal is to translate the newly available technology to industrial prototypes and ultimately commercial markets. In this talk we will be reporting on the scientific and technological scope of the Hub and how we plan to further develop technology platforms, sensor schemes and prototype devices within the consortium, together with the large number of involved industrial partners.

14:30 Murray Barrett, CQT, NUS
A Better Optical Clock Candidate.
Arrow Abstract

With the extreme precision now reached by optical clocks it is reasonable to consider redefinition of the frequency standard. In doing so it is important to look beyond the current best-case efforts and have an eye on future possibilities. We will argue that singly ionized Lutetium is a strong candidate for the next generation of optical frequency standards. Lu$+$ has a particularly narrow optical transition in combination with several advantageous properties for managing systematic uncertainties compared to the other atomic species. We summarize these properties and our specific strategies for managing the uncertainties due to external perturbations. Finally, we present the status of our ongoing experiments with trapped Lu$+$, including the results of precision measurements of its atomic structure.

15:00 Coffee/Tea Break & Discussions

Centre for quantum technologies National University of Singapore