External seminar archive


Towards a two-dimensional spin photon interface

11 July 2022
Dr Hannah Stern, University Of Cambridge
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Sub-wavelength quantum imaging for astronomy

24 August 2022

Dr Zixin Huang, Macquarie University, Sydney, Australia

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The resolution limit of standard imaging techniques is expressed by the Rayleigh criterion, which states that two point-like sources are difficult to resolve if their transverse separation is smaller than the Rayleigh length. While the criterion is useful in the case of direct detection imaging, other measurement techniques may not be subject to this limitation. Estimating the angular separation between two sources is a challenging task for direct imaging, especially when their angular separation is smaller than or comparable to the Rayleigh limit. In addition, if one is tasked with first discriminating whether there are one or two sources, then detecting the faint emission of a secondary source in the proximity of a much brighter one is in itself a severe challenge for direct imaging.

Using quantum state discrimination and quantum imaging techniques, we show that one can significantly reduce the probability of error for detecting the presence of a weak secondary source, especially when the two sources have small angular separations. If the weak source has intensity ε≪1 relative to the bright source, we find that the error exponent can be improved by a factor of 1/ε. We also find linear-optical measurements that are optimal in this regime [1]. We apply these techniques to LIDAR [2] as well as exoplanet detection.

We then experimentally demonstrate clear sub-Rayleigh scaling for quantum state discrimination of singular versus binary sources, and we approach the quantum Cramer-Rao bound for estimating the angular separation of two sources with equal brightness. Most importantly, the two tasks can be achieved with a single measurement setup: all the above tasks can be performed with a simple interferometer [3].

[1] Z Huang, C Lupo, Phys. Rev. Lett. 127, 130502 (2021); Editor's Selection and Featured in Physics.

[2] Z Huang, C Lupo, P Kok, PRX Quantum 2 (3), 030303 (2021)

[3] U Zanforlin, C Lupo, P Connolly, P Kok, G Buller, and Z Huang, accepted in Nat. Comm. (2022); arXiv:2202.09406


Simulating synthetic dimensions and topological physics in photonics (online)

30 November 2020
Dr Hannah Price, University Of Birmingham
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A coherent mechanical oscillator driven by single-electron tunnelling (online)

26 October 2020
Dr Edward Laird, Lancaster University
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Hybrid quantum photonics with nanodiamonds and plasmons (online)

15 October 2020
Dr Hamidreza Siampour, the University Of Sheffield
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Nuclear spins: A collective ancilla memory for semiconductor quantum dots?

4 October 2019
Dr Claire Le Gall, University Of Cambridge
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Tammtronics: Quantum light sources and photodetectors based on Tamm plasmons

13 September 2019
Dr Edmund Harbord, University Of Bristol
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Dielectric nanocavities for enhanced Purcell effect and strong directionality

3 July 2019
Dr Riccardo Sapienza, Imperial College of Science and Technology
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Bose-Einstein condensation of just a few photons

23 May 2019
Dr Benjamin Walker, Imperial College London
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Fred Combley Colloquium - Professor Jonathan Knight

15 May 2019
Professor Jonathan Knight, University Of Bath

Mesoporous gallium nitride

30 April 2019
Professor Rachel Oliver, University Of Cambridge
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Perfect topological protection in photonic multilayers and transmission line networks

3 April 2019
Professor David Whittaker, the University Of Sheffield

Analogue physics with topological defects in Bose-Einstein condensates

14 March 2019
Dr Dmitry Solnyshkov, Institut Pascal, University Clermont Auvergne/CNRS, Clermont-Ferrand, France
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Spin conversion phenomena in spintronics

5 February 2019
Professor Y Otani, The University Of Tokyo
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Using strain-enabled collective nuclear spin waves as a quantum memory

11 January 2019
Emil Denning, Technical University Of Denmark
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Piezoelectric platforms for optomechanics

21 November 2018
Dr Krishna Balram, University Of Bristol
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LDSD Seminar - Dr Anthony Laing

1 November 2018
Dr Anthony Laing, University Of Bristol

Single electron pumps: Current standards, tomography of single electron wavepackets and electron quantum optics

24 October 2018
Dr Jonathan Fletcher, Quantum Detection Group, National Physical Laboratory
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LDSD Seminar - Dr Konstantinos Lagoudakis

11 October 2018
Dr Konstantinos Lagoudakis, University Of Strathclyde

LDSD Seminar - Professor Goki Eda

3 July 2018
Professor Goki Eda, National University Of Singapore
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LDSD Seminar - Dr Alberto Politi

6 June 2018
Dr Albert Politi, University Of Southampton

Metamaterials for topological photonics

17 May 2018
Professor Shuang Zhang, University Of Birmingham
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LDSD Seminar

20 March 2018
Dr Philip King, University Of St Andrews

Combley Lecture - Professor Jonathan Finley

14 March 2018
Professor Dr Jonathan Finley, TU Munich

A polariton graph optimiser

7 February 2018
Professor Natalia Berloff, University Of Cambridge
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Terahertz frequency quantum cascade lasers - from devices to applications

22 November 2017
Professor Edmund Linfield, University Of Leeds
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LDSD Seminar - Dr Marzena Szymanska

15 November 2017
Dr Marzena Szymanska, University College London

The potential of type-II systems for third generation photovoltaics: Hot carrier absorbers and intermediate band solar cells

9 November 2017
Professor Ian R Sellers, University Of Oklahoma
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LDSD Seminar - Dr Jan Huwer

11 October 2017
Dr Jan Huwer, Cambridge Research Laboratory, Toshiba Research Europe Ltd.

Organic molecular quantum technologies

13 June 2017
Dr Alex Clark, Imperial College, London
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Chip in a fridge: Why useful complex quantum systems need cryogenics

30 May 2017
Dr Jorge Barreto, University Of Bristol
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Strained graphene and molecular adsorption on boron nitride

24 May 2017
Professor Peter Beton, University Of Nottingham
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Rydberg excitons in cuprous oxide - Fred Combley Colloquium

4 May 2017
Professor Manfred Bayer, TU Dortmund
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Generation of mechanical interference fringes by multi-photon quantum measurement

6 April 2017
Dr Michael Vanner, University Of Oxford
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Amplitude/frequency modulation and detection of THz quantum cascade lasers with hybrid metamaterial/graphene integrated arrays

23 February 2017
Dr Riccardo Degl'Innocenti, University Of Cambridge
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