Academics

Welcome

I am a Fellow and Tutor in Physics at Keble College and a University Lecturer in Experimental Quantum Physics within the Physics Department at the University of Oxford. My research interests lie broadly in the areas of experimental optical and quantum physics – ranging from implementations of quantum information protocols with optical systems, studying fundamental quantum physics using optical means, to improving optical measurement techniques. For more information on my research please visit the Oxford Quantum Technologies Laboratory website or feel free to contact me directly (email preferred).

Research Interests

Quantum physics plays an ever-increasing role in applied fields such as metrology, lithography, and with continually decreasing circuit sizes, information technology. This has ushered in the “second quantum revolution” with several emergent research areas including nanotechnology and quantum metrology. Quantum-enhanced technologies, based upon the laws obeyed by elementary particles, represent a key element to technological advances of the next century. These technologies aim to take advantage of the “strange” properties of the quantum world, wave-particle duality and entanglement, which have no classical counterpart. Broadly speaking, quantum technologies enable tasks that cannot be performed with classical resources, such as exponentially-fast computation, increased resolution beyond the shot-noise limit, physically-secure cryptography and non-interactive measurements. Many of these technologies, such as precision metrology and quantum communications, naturally lend themselves to optical implementations, while others, such as quantum relays and distributed quantum computation, will rely on light for auxiliary, but necessary tasks. It is within these general areas of optical quantum technologies that I carry out experimental and theoretical research. This work ranges from specific device development – such as non-classical light sources – to enquiry of the fundamental principles of quantum theory, e.g. probing the nature of entanglement.

Recent Publications

• C. Söller, O. Cohen, B. J. Smith, I. A. Walmsley, and Ch. Silberhorn, 'High-performance single-photon generation with commercial-grade optical fiber' in Phys. Rev. A, 83 (2011), 031806(R)
• N. Thomas-Peter, N. K. Langford, A. Datta, L. Zhang, B. J. Smith, J. B. Spring, B. J. Metcalf, H. B. Coldenstrodt-Ronge, M. Hu, J. Nunn and I. A. Walmsley, 'Integrated Photonic Sensing' in New J. Phys., 13 (2011), 055024
• A. Datta, L. Zhang, N. Thomas-Peter, U. Dorner, B. J. Smith, I. A. Walmsley, 'Quantum metrology with imperfect states and detectors' in Phys. Rev. A, 83 (2011), 063836
• N. Thomas-Peter, B. J. Smith, A. Datta, L. Zhang, U. Dorner, and I. A. Walmsley, 'Real-world Quantum Sensors: Evaluating Resources for Precision Measurement' in Phys. Rev. Lett., 107 (2011), 133902
• J. Nunn, B. J. Smith, G. Puentes, I. A. Walmsley, and J. S. Lundeen, 'Optimal experiment design for quantum state tomography: Fair, precise, and minimal tomography' in Phys. Rev. A, 81 (2010), 042109
• B. J. Smith, P. Mahou, O. Cohen, J. S. Lundeen, and I. A. Walmsley, “Photon pair generation in birefringent optical fibers, 'Photon pair generation in birefringent optical fibers' in Opt. Express, 17 (2009), 23589–23602
• B. J. Smith, D. Kundys, N. Thomas-Peter, P. G. R. Smith, and I. A. Walmsley, 'Phase-controlled integrated photonic quantum circuits' in Opt. Express, 17 (2009), 13516-13525
• R. Demkowicz-Dobrzanski, U. Dorner, B. J. Smith, J. S. Lundeen, W. Wasilewski, K. Banaszek, and I. A. Walmsley, 'Quantum phase estimation with lossy interferometers' in Phys. Rev. A, 80 (2009), 013825
• O. Cohen, J. S. Lundeen, B. J. Smith, G. Puentes, P. J. Mosley and I. A. Walmsley, 'Tailored photon-pair generation in optical fibers' in Phys. Rev. Lett., 102 (2009), 123603
• A. P. Worsley, H. B. Coldenstrodt-Ronge, J. S. Lundeen, P. J. Mosley, B. J. Smith, G. Puentes, N. Thomas-Peter, and I. A. Walmsley, 'Absolute efficiency estimation of photon-number-resolving detectors using twin beams' in Opt. Express, 17 (2009), 4397-4411
• G. Puentes, J. S. Lundeen, M. P. A. Branderhorst, H. B. Coldenstrodt-Ronge, B. J. Smith, and I. A. Walmsley, 'Bridging Particle and Wave Sensitivity in a Configurable Detector of Positive Operator-Valued Measures' in Phys. Rev. Lett., 102 (2009), 080404
• P. J. Mosley, J. S. Lundeen, B. J. Smith, and I. A. Walmsley, 'Focusing on factorability: Space-time coupling in the generation of pure heralded single photons' in J. Mod. Opt., 56 (2009), 179-189
• H. Coldenstrodt-Ronge, J. S. Lundeen, K. L. Pregnell, A. Feito, B. J. Smith, W. Mauerer, C. Silberhorn, J. Eisert, M. B. Plenio, and I. A. Walmsley, 'A proposed testbed for detector tomography' in J. Mod. Opt., 56 (2009), 432-441
• U. Dorner, R. Demkowicz-Dobrzanski, B. J. Smith, J. S. Lundeen, K. Banaszek, and I. A. Walmsley, 'Optimal quantum phase estimation' in Phys. Rev. Lett., 102 (2009), 040403
• P. J. Mosley, J. S. Lundeen, B. J. Smith, and I. A. Walmsley, 'Conditional preparation of single photons using parametric downconversion: a recipe for purity' in New J. Phys., 10 (2008), 093011
• P. J. Mosley, J. S. Lundeen, B. J. Smith, P. Wasylczyk, A. B. U’Ren, C. Silberhorn, and I. A. Walmsley, 'Heralded generation of ultrafast single photons in pure quantum states' in Phys. Rev. Lett., 100 (2008), 133601
• B. J. Smith and M. G. Raymer, 'Photon wave functions, wave-packet quantization of light, and coherence theory' in New J. Phys., 9 (2007), 414

Academic Biography

• University Lecturer in Experimental Quantum Physics and Tutorial Fellow, Department of Physics and Keble College, University of Oxford, Oxford, UK (2010 - present)
• Research Fellow, Centre for Quantum Technologies, National University of Singapore, Singapore (2009 - 2010)
• Royal Society USA Postdoctoral Research Fellow, University of Oxford, Oxford, UK (2007 - 2009)
• Graduate Research Fellow, University of Oregon, USA (2002 - 2007)