Imperial College London

Emeritus Professor SirPeterKnight

Faculty of Natural SciencesDepartment of Physics

Senior Research Investigator
 
 
 
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Contact

 

+44 (0)20 7594 7727p.knight Website

 
 
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Location

 

206Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

359 results found

Bergmann K, Eberly JH, Halfmann T, Knight PL, Vitanov NVet al., 2023, Editorial note for the J. Phys. B. special issue 'Coherent Control: Photons, Atoms and Molecules' honoring the life and work of Bruce W Shore, JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, Vol: 56, ISSN: 0953-4075

Journal article

Alsing PM, Birrittella RJ, Gerry CC, Mimih J, Knight PLet al., 2022, Extending the Hong-Ou-Mandel effect: the power of nonclassicality, Physical Review A: Atomic, Molecular and Optical Physics, Vol: 105, ISSN: 1050-2947

We show that the parity (evenness or oddness) of a nonclassical state of light has a dominant influence on the interference effects at a balanced beam splitter, irrespective of the state initially occupying the other input mode. Specifically, the parity of the nonclassical state gives rise to destructive interference effects that result in deep valleys in the output joint number distribution of which the Hong-Ou-Mandel (HOM) effect is a limiting case. The counterintuitive influence of even a single photon to control the output of a beam splitter illuminated by any field, be it a coherent or even a noisy thermal field, demonstrates the extraordinary power of nonclassicality. The canonical example of total destructive interference of quantum amplitudes leading to the absence of coincidence counts from a 50:50 beam splitter (BS) is the celebrated HOM effect, characterized by the vanishing of the joint probability of detecting singe photons in each of the output beams. We show that this is a limiting case of more general input states upon which a 50:50 BS can create total, or near total, destructive interference of quantum amplitudes. For the case of an odd photon-number input Fock state of arbitrary value n>0 we show that the joint photon-number probabilities vanish when detecting identical photon numbers in each output beams. We specifically examine the mixing of photon-number states of n=1, 2, and 3 with a continuous-variable state, such as a coherent state of arbitrary amplitude, and a thermal state. These vanishing joint probabilities form what we call a central nodal line: A contiguous set of zeros representing complete destructive interference of quantum amplitudes. We further show that with odd or even photon-number Fock states n, with n>1, there will be additional off-diagonal curves along which the joint photon-number probabilities are either zero, or near zero, which we call pseudonodal curves, which constitute a near, but not complete, destructive inte

Journal article

Danson CN, White M, Barr JRM, Bett T, Blyth P, Bowley D, Brenner C, Collins RJ, Croxford N, Dangor AEB, Devereux L, Dyer PE, Dymoke-Bradshaw A, Edwards CB, Ewart P, Ferguson AI, Girkin JM, Hall DR, Hanna DC, Harris W, Hillier DI, Hooker CJ, Hooker SM, Hopps N, Hull J, Hunt D, Jaroszynski DA, Kempenaars M, Kessler H, Knight PL, Knight S, Knowles A, Lewis CLS, Lipton KS, Littlechild A, Littlechild J, Maggs P, Malcolm GPA, Mangles SPD, Martin W, McKenna P, Moore RO, Morrison C, Najmudin Z, Neely D, New GHC, Norman MJ, Paine T, Parker AW, Penman RR, Pert GJ, Pietraszewski C, Randewich A, Rizvi NH, Seddon N, Sheng Z-M, Slater D, Smith RA, Spindloe C, Taylor R, Thomas G, Tisch JWG, Wark JS, Webb C, Wiggins SM, Willford D, Winstone Tet al., 2021, A history of high-power laser research and development in the United Kingdom, High Power Laser Science and Engineering, Vol: 9, Pages: 1-86, ISSN: 2095-4719

The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

Journal article

Knight P, Walmsley I, 2019, UK national quantum technology programme, Quantum Science and Technology, Vol: 4, Pages: 1-9, ISSN: 2058-9565

The UK has, through a mix of government and industry funding, committed more than £1Bn over ten years to a coordinated programme in quantum technology. Five years into this programme, the UK National Quantum Technology Programme has induced a step change in the nation's capabilities for establishing a new sector in future quantum information technologies. We describe how the programme arose and the activities it has supported and influenced to deliver these new capabilities, building on a first phase of over £385M investment across several UK government agencies. As the programme enters its second phase, with a further substantial investment by UK government and global industries, we review the prospects for ensuring the advanced quantum science and demonstrator platforms in imaging, sensing, timing, communications and computing developed over the past five years drive the formation of the sector and embed quantum tech in a broad range of industries by means of new products and services.

Journal article

Xia K, Johnsson M, Knight PL, Twamley Jet al., 2016, Cavity-free scheme for nondestructive detection of a single optical photon, Physical Review Letters, Vol: 116, ISSN: 1079-7114

Detecting a single photon without absorbing it is a long-standing challenge in quantum optics. All experiments demonstrating the nondestructive detection of a photon make use of a high quality cavity. We present a cavity-free scheme for nondestructive single-photon detection. By pumping a nonlinear medium we implement an interfield Rabi oscillation which leads to a ∼π phase shift on a weak probe coherent laser field in the presence of a single signal photon without destroying the signal photon. Our cavity-free scheme operates with a fast intrinsic time scale in comparison with similar cavity-based schemes. We implement a full real-space multimode numerical analysis of the interacting photonic modes and confirm the validity of our nondestructive scheme in the multimode case.

Journal article

Angelakis DG, Beige A, Knight PL, Munro WJ, Tregenna Bet al., 2014, Verifying atom entanglement schemes by testing Bell's inequality, 3rd International Workshop on Mysteries, Puzzles and Paradoxes in Quantum Mechanics, Publisher: WALTER DE GRUYTER GMBH, Pages: 27-34, ISSN: 0932-0784

Conference paper

Henkel J, Witting T, Fabris D, Lein M, Knight PL, Tisch JWG, Marangos JPet al., 2013, Prediction of attosecond light pulses in the VUV range in a high-order-harmonic-generation regime, PHYSICAL REVIEW A, Vol: 87, ISSN: 1050-2947

Journal article

Genoni MG, Paris MGA, Adesso G, Nha H, Knight PL, Kim MSet al., 2013, Optimal estimation of joint parameters in phase space, Physical Review A, Vol: 87, ISSN: 1094-1622

We address the joint estimation of the two defining parameters of a displacement operation in phase space. In a measurement scheme based on a Gaussian probe field and two homodyne detectors, it is shown that both conjugated parameters can be measured below the standard quantum limit when the probe field is entangled. We derive the most informative Cramér-Rao bound, providing the theoretical benchmark on the estimation, and observe that our scheme is nearly optimal for a wide parameter range characterizing the probe field. We discuss the role of the entanglement as well as the relation between our measurement strategy and the generalized uncertainty relations.

Journal article

Chipperfield LE, Robinson JS, Knight PL, Marangos JP, Tisch JWGet al., 2010, The generation and utilization of half-cycle cut-offs in high harmonic spectra, LASER & PHOTONICS REVIEWS, Vol: 4, Pages: 697-719, ISSN: 1863-8880

Journal article

Haigh J, Bradley D, Knight P, 2009, RAE wranglings provoke debate, PHYSICS WORLD, Vol: 22, Pages: 19-19, ISSN: 0953-8585

Journal article

Marzlin K-P, Sanders BC, Knight PL, 2008, Complementarity and uncertainty relations for matter-wave interferometry, PHYSICAL REVIEW A, Vol: 78, ISSN: 1050-2947

Journal article

JOO J, KNIGHT P, O'BRIEN J, Rudolph Tet al., 2007, One-way quantum computation with four-dimensional photonic qudits, Physical Review A, Vol: 76, ISSN: 1050-2947

We consider the possibility of performing linear optical quantum computations making use of extra photonic degrees of freedom. In particular, we focus on the case where we use photons as quadbits, four-dimensional photonic qudits. The basic 2-quadbit cluster state is a hyperentangled state across polarization and two spatial mode degrees of freedom. We examine the nondeterministic methods whereby such states can be created from single photons and/or Bell pairs and then give some mechanisms for performing higher-dimensional fusion gates.

Journal article

Fermani R, Scheel S, Knight PL, 2007, Trapping cold atoms near carbon nanotubes: Thermal spin flips and Casimir-Polder potential, PHYSICAL REVIEW A, Vol: 75, ISSN: 1050-2947

Journal article

Scheel S, Florescu M, Haffner H, Lee H, Strekalov DV, Knight PL, Dowling JPet al., 2007, Single photons on demand from tunable 3D photonic band-gap structures, JOURNAL OF MODERN OPTICS, Vol: 54, Pages: 409-416, ISSN: 0950-0340

Journal article

Haworth CA, Chipperfield LE, Robinson JS, Knight PL, Marangos JP, Tisch JWGet al., 2007, Half-cycle cutoffs in harmonic spectra and robust carrier-envelope phase retrieval, NATURE PHYSICS, Vol: 3, Pages: 52-57, ISSN: 1745-2473

Journal article

Joo J, Knight PL, Pachos JK, 2007, Single atom quantum walk with 1D optical superlattices, JOURNAL OF MODERN OPTICS, Vol: 54, Pages: 1627-1638, ISSN: 0950-0340

Journal article

Segal DM, Knight PL, Meschede D, 2007, Quantum information processing using selectively addressed atoms - Perface, JOURNAL OF MODERN OPTICS, Vol: 54, Pages: 1537-1540, ISSN: 0950-0340

Journal article

Joo J, Lim YL, Beige A, Knight PLet al., 2006, Single-qubit rotations in two-dimensional optical lattices with multiqubit addressing, PHYSICAL REVIEW A, Vol: 74, ISSN: 1050-2947

Journal article

Chipperfield LE, Knight PL, Tisch JWG, Marangos JPet al., 2006, Tracking individual electron trajectories in a high harmonic spectrum, OPTICS COMMUNICATIONS, Vol: 264, Pages: 494-501, ISSN: 0030-4018

Journal article

Florescu M, Scheel S, Lee H, Knight PL, Dowling JPet al., 2006, Nonlinear tuning of 3D photonic band-gap structures for single-photon on demand sources, 12th International Conference on Modulated Semiconductor Structures (MSS12), Publisher: ELSEVIER, Pages: 484-487, ISSN: 1386-9477

Conference paper

Fermani R, Scheel S, Knight PL, 2006, Spatial decoherence near metallic surfaces, PHYSICAL REVIEW A, Vol: 73, ISSN: 1050-2947

Journal article

Knight PL, Marangos JP, 2006, High Field Attosecond Physics, Obergurgl, 2005 - Preface, JOURNAL OF MODERN OPTICS, Vol: 53, Pages: 1-1, ISSN: 0950-0340

Journal article

Florescu M, Scheel S, Lee H, Knight PL, Bowling JPet al., 2006, Three-dimensional photonic band-gap structures for single-photon on demand sources, 8th International Conference on Transparent Optical Networks, Publisher: IEEE, Pages: 40-+

Conference paper

Scheel S, Fermani R, Rekdal PK, Knight PL, Hinds EAet al., 2006, Atomic spin relaxation and spatial decoherence near metallic and superconducting surfaces, 12th Central European Workshop on Quantum Optics, Publisher: IOP PUBLISHING LTD, Pages: 188-+, ISSN: 1742-6588

Conference paper

Scheel S, Pachos JK, Hinds EA, Knight PLet al., 2006, Quantum gates and decoherence, Publisher: Springer-Verlag Berlin, Pages: 47-81

Book chapter

Scheel S, Pachos JK, Hinds EA, Knight PLet al., 2006, Quantum gates and decoherence, Quantum Coherence: from Quarks to Solids, Vol: 689, Pages: 47-81, ISSN: 0075-8450

Journal article

Scheel S, Pachos JK, Hinds EA, Knight PLet al., 2006, Quantum gates and decoherence, Quantum Coherence: from Quarks to Solids, Vol: 689, Pages: 47-81, ISSN: 0075-8450

Journal article

Knight PL, Scheel S, 2006, Quantum information (In press), Springer handbook of atomic, molecular, and optical physics, Editors: Drake, Drake, Publisher: Springer, Pages: 1219-1234, ISBN: 9780387208022

Book chapter

Knight PL, 2005, The observation of matter wave fluctuations, SCIENCE, Vol: 310, Pages: 631-632, ISSN: 0036-8075

Journal article

Shore BW, Knight PL, 2005, Surprises in physics: Overturning conventional wisdom, LASER PHYSICS, Vol: 15, Pages: 1448-1457, ISSN: 1054-660X

Journal article

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