Thursday, 27 April 2017

Day 3 of the Bristol Quantum Information Technologies (BQIT) workshop

Almut Beige (University of Leeds) and her talk "from optical cavities to cavity-fibre networks"

BQIT:17's third and final day saw the workshop draw to a close with another sunny day of talks on detectors, hybrid platforms and integrated photonics.

Kicking things off was Sae Woo Nam from NIST. Sae Woo explained two projects around the subject of superconducting nanowire single photon detectors (SNSPDs): one which showed a detection efficiency when used in practice of over 93%, and another on SNSPDs integrated into waveguides. He finished talking about some work with Dave Wineland integrating these detectors with ion traps. University of Münster's Wolfram Pernice followed this by speaking about developing SNSPDs which are capable of detecting single photons in plane, making them suitable for waveguides.

The first solid state & hybrid systems session began with Almut Beige from the University of Leeds, who explained how we can better understand how to couple optical cavities from working out the Hamiltonian of a beam splitter. She was followed by the University of Bristol's own Ruth Oulton discussing her group's work using a quantum dot to switch the polarisation of a single photon, where they were able to achieve 80% efficiency. Sven Hofling from the University of Wurzburg concluded this segment talking about using quantum dots as single photon sources.

After lunch, the integrated quantum photonics section started with Sébastien Tanzilli from the University of Nice, who explained their recent results on generating two-photon N00N states. These states were then used to measure chromatic dispersion in an optical fibre with more than twice the precision even though there were sixty times as fewer photons. This was followed by the Raffaele Santagati from the University of Bristol. Raffaele introduced WAVES, a witness assisted eigenvalue solver capable of successfully estimating phase with an error of ​ radians, even in the presence of noise.

The final talks of the workshop formed our second session on hybrid & solid state systems. Jason Smith from the University of Oxford, spoke about coupling photons in microcavities with NV centres in nanodiamond, producing a 97% purity room temperature single photon source. Finally, Peter Humphreys from Delft University of Technology explained work on using entanglement distillation to create better entangled NV centres, as a step towards a large scale quantum network following their 13km Bell violation.

Proceedings were closed by Professor John Rarity FRS, director of QET Labs.

Thank you to everyone who joined us this year and for helping to make our workshop a success.

Save the date for next year's BQIT workshop: 18-20 April 2018

Our workshop venue, M Shed, on Bristol's harbourside
For photos of BQIT:17 please visit:
Videos of all of our talks from the workshop are also available at:
For information on upcoming events, or for more information and queries please email us at

Day 2 of the Bristol Quantum Information Technologies (BQIT) workshop

Our BQIT student helpers (left to right) Jorge Monroy Ruz, Caterina Vigliar and Ben Slater

Day 2 of QET Labs' fourth annual Bristol Quantum Information Technologies (BQIT) saw another sunny day of talks related to quantum technologies.

The quantum information theory stream kicked off with the University of Bristol's Ashley Montanaro, detailing two recent algorithms to provide quadratic speedups for backtracking and Monte Carlo methods. This was followed by Ulm University's Martin Plenio, who talked about efficient ways of performing quantum state tomography, resulting in being able to experimentally demonstrate efficient state tomography for 20 trapped ions. Laura Mancinska, also of the University of Bristol, concluded this topic with a talk on how to verify that a state you are given is entangled.

A coffee break precluded Winfried Hensinger of the University of Sussex, who began the scaling up theme by explaining the background of ion trap quantum computing, before introducing his blueprint for constructing a large-scale quantum computer. This was followed by the University of Technology Sydney's Michael Bremner describing the notion of instantaneous quantum polynomial time, and his collaboration with Google to determine what exactly is needed to reach quantum supremacy in the near future.

After lunch, the metrology session began with ICFO's Morgan Mitchell, who explained how to achieve spin states which are squeezed in multiple components, thus beating the quantum limit. These states could then be used to help with gravitational wave detection. Alex Lvovsky from the University of Calgary followed up by highlighting several of his group's experiments, showing some of the many things you can do with a Schroedinger's cat state.

A session on continuous variable quantum photonics began with Akira Furusawa from the University of Tokyo describing the work by his group to develop continuous variable quantum teleportation on a photonic chip, as a possible way of realising large-scale measurement-based quantum computing. This was followed by the QETLabs' own Dylan Mahler, who discussed recent work at the University of Bristol on efficient homodyne detection, in particular using it to measure the vacuum state for a quantum random number generator.

The day ended with Tommaso Calarco from Ulm University, who explained the current status of the Quantum Flagship Project, a project by the European Commission to offer €1billion of funding for quantum technologies.

Akira Furusawa (University of Tokyo) and his talk on hybrid quantum information processing
For photos of BQIT:17 please visit:
Videos of all of our talks from the workshop are also available at:
For information on upcoming events, or for more information and queries please email us at

Day 1 of the Bristol Quantum Information Technologies (BQIT) workshop

This year's BQIT workshop was hosted at the M Shed on Bristol's harbourside.

The first day of QET Labs' fourth annual Bristol Quantum Information Technologies (BQIT) Workshop kicked off with a whistle-stop tour of quantum technologies, ranging from the foundations of entanglement to the quantum industry.

For entanglement foundations, first to speak was University of Toronto's Aephraim Steinberg, highlighting two recent results: how quantum-enhanced sensing can beat "Rayleigh's curse" and strongly increase nonlinear optical effects. He was followed by Marek Żukowski from the University of Gdańsk, who explained how redefining Stokes parameters can lead to better entanglement observations.

The devices segment began with Josh Nunn from the University of Oxford unveiling a long awaited result: A noise free quantum memory! University of Pavia's Marco Liscidini followed this with his proposal for a ring resonator with 99.9% purity.

Our first information theorist of the workshop, Caltech's Elizabeth Crosson spoke about not only how quantum annealing can outperform simulated annealing, but even how classical techniques inspired by quantum annealing can provide speedups over simulated annealing.

Following lunch, Jake Kennard of QET Labs started by speaking about quantum cryptography in integrated silicon, focusing in particular on a secret key rate of 1megabit/s from a chip smaller than a 5p coin! Robert Collins from Heriot Watt University explained recent work on implementing quantum digital signatures on kilometre networks around the world. The communications segment concluded with the Russian Quantum Centre's Yury Kurochkin explaining their proposed products for commercial quantum key distribution.

Chris Erven, deputy director of the Quantum Technology Enterprise Centre (QTEC), began our industry segment by talking about the past year of QTEC and his advocacy for "white-hat tweeting". From a fundamental company for quantum photonics, Chris Snelling of ICE Oxford detailed the largest and most powerful cryostat they have ever made, offering 340mW of colling power at 1.0K. Our final talk for the day came from Keysight Technologies' Niki Haines, who explained the platforms Keysight thought were most likely to mainstream quantum computers, and the tools they were developing to help reach this goal.

The day concluded with a panel discussion on the state of the quantum industry. Questions ranged from how the industry has (and will continue to) change, to what academics and universities should do to enter the commercial world, and what would the panellists consider to be quantum technology in the first place.

Our Industry panel (left to right) Susannah Jones from DSTL, Roberto Desimone from BAE Systems, Bob Cockshott from KTN UK, Niki Haines from Keysight and Andy Collins from QTEC.
For photos of BQIT:17 please visit:
Videos of all of our talks from the workshop are also available at:
For information on upcoming events, or for more information and queries please email us at