What is a quantum computer, and how do we build one? (2009)
Perez-Delgado, Carlos A., Kok, Pieter
The DiVincenzo criteria for implementing a quantum computer have been seminal in focussing both experimental and theoretical research in quantum information processing. These criteria were formulated...
We demonstrate theoretically a scheme for cluster state generation, based on atomic ensembles and the dipole blockade mechanism. In the protocol, atomic ensembles serve as single qubit systems....
Entanglement Swapping as Event-Ready Entanglement Preparation (2008)
Pieter Kok, Samuel L. Braunstein
In this contribution the preparation of event-ready entanglement in polarised photons by means of entanglement swapping is studied. This protocol makes use of Gaussian photon-sources. Since the...
Cluster state generation with atomic ensembles via the dipole blockade mechanism (2008)
We present a new scheme for cluster states generation based on atomic ensembles and the dipole blockade mechanism. The protocol requires identical single photon sources, one ensemble per physical...
Dr. Techn Michael Drmota, Gerard Johan, Pieter Kok
The distribution of patterns in random trees ausgeführt am Institut für Diskrete Mathematik und Geometrie
Linear Optics and Projective Measurements for Fun and Profit (2008)
Pieter Kok, Hwang Lee, Colin P. Williams, Jonathan P. Dowling
The technique of projective measurements in linear optics can provide apparent, efficient nonlinear interaction between photons, which is technically problematic otherwise. We present an application...
Effects of self-phase modulation on weak nonlinear optical quantum gates (2007)
A possible two-qubit gate for optical quantum computing is the parity gate based on the weak Kerr effect. Two photonic qubits modulate the phase of a coherent state, and a quadrature measurement of...
Lecture notes on Optical Quantum Computing (2007)
A quantum computer is a machine that can perform certain calculations much faster than a classical computer by using the laws of quantum mechanics. Quantum computers do not exist yet, because it is...
Efficient growth of complex graph states via imperfect path erasure (2007)
Campbell, Earl T., Fitzsimons, Joseph, Benjamin, Simon C., Kok, Pieter
Given a suitably large and well connected (complex) graph state, any quantum algorithm can be implemented purely through local measurements on the individual qubits. Measurements can also be used to...
Linear optical quantum computing with photonic qubits (2007)
Kok, Pieter, Munro, W. J., Nemoto, K.ae, Dowling, Jonathon P., Milburn, G. J.
Linear optics with photon counting is a prominent candidate for practical quantum computing. The protocol by Knill, Laflamme, and Milburn [2001, Nature (London) 409, 46] explicitly demonstrates that...
Linear optical quantum computing with photonic qubits (2007)
Kok, Pieter, Munro, W. J., Nemoto, K.ae, Dowling, Jonathon P., Milburn, G. J.
Linear optics with photon counting is a prominent candidate for practical quantum computing. The protocol by Knill, Laflamme, and Milburn [2001, Nature (London) 409, 46] explicitly demonstrates that...
Adaptive strategies for graph state growth in the presence of monitored errors (2006)
Campbell, Earl T., Fitzsimons, Joseph, Benjamin, Simon C., Kok, Pieter
Graph states (or cluster states) are the entanglement resource that enables one-way quantum computing. They can be grown by projective measurements on the component qubits. Such measurements...
Creating large noon states with imperfect phase control (2006)
Optical noon states (|N,0> + |0,N>) are an important resource for Heisenberg-limited metrology and quantum lithography. The only known methods for creating noon states with arbitrary $N$ via linear...
Review article: Linear optical quantum computing (2005)
Kok, Pieter, Munro, W. J., Nemoto, Kae, Ralph, T. C., Dowling, Jonathan P., Milburn, G. J.
Linear optics with photon counting is a prominent candidate for practical quantum computing. The protocol by Knill, Laflamme, and Milburn [Nature 409, 46 (2001)] explicitly demonstrates that...
Repeat-Until-Success quantum computing using stationary and flying qubits (2005)
Lim, Yuan Liang, Barrett, Sean D., Beige, Almut, Kok, Pieter, Kwek, Leong Chuan
We introduce an architecture for robust and scalable quantum computation using both stationary qubits (e.g. single photon sources made out of trapped atoms, molecules, ions, quantum dots, or defect...
Quantum Interferometric Sensors (2005)
Kapale, Kishore T., Didomenico, Leo D., Lee, Hwang, Kok, Pieter, Dowling, Jonathan P.
Quantum entanglement has the potential to revolutionize the entire field of interferometric sensing by providing many orders of magnitude improvement in interferometer sensitivity. The...
Preparing multi-partite entanglement of photons and matter qubits (2005)
Kok, Pieter, Barrett, Sean D., Spiller, Timothy P.
We show how to make event-ready multi-partite entanglement between qubits which may be encoded on photons or matter systems. Entangled states of matter systems, which can also act as single photon...
Efficient optical quantum information processing (2005)
Munro, W. J., Nemoto, Kae, Spiller, T. P., Barrett, S. D., Kok, Pieter, Beausoleil, R. G.
Quantum information offers the promise of being able to perform certain communication and computation tasks that cannot be done with conventional information technology (IT). Optical Quantum...
Quantum interferometric sensors (2005)
Kishore T. Kapale, Leo D. Didomenico, Hwang Lee, Pieter Kok, Jonathan P. Dowling
Quantum entanglement has the potential to revolutionize the entire field of interferometric sensing by providing many Concepts of Physics, Vol. II (2005) 225 orders of magnitude improvement in...
Efficient high-fidelity quantum computation using matter qubits and linear optics (2004)
We propose a practical, scalable, and efficient scheme for quantum computation using spatially separated matter qubits and single photon interference effects. The qubit systems can be NV-centers in...
Relativistic quantum communication with bosonic and fermionic interferometers (2004)
Kok, Pieter, Braunstein, Samuel L.
We derive the relativistic transformation laws for the annihilation operators of the scalar field, the massive spin-1 vector field, the electromagnetic field and the spinor field. The technique...
Communicating continuous quantum variables between different Lorentz frames (2004)
Kok, Pieter, Ralph, Timothy C., Milburn, Gerard J.
We show how to communicate Heisenberg-limited continuous (quantum) variables between Alice and Bob in the case where they occupy two inertial reference frames that differ by an unknown Lorentz boost....
Comment on: "Measuring a Photonic Qubit without Destroying It" (2004)
Kok, Pieter, Munro, William J.
Recently, Pryde et al reported the demonstration of a quantum non-demolition scheme for single-photon polarization states with linear optics and projective measurements [Phys. Rev. Lett. 92, 190402...
Quantum lithography, entanglement and Heisenberg-limited parameter estimation (2004)
Kok, Pieter, Braunstein, Samuel L., Dowling, Jonathan P.
We explore the intimate relationship between quantum lithography, Heisenberg-limited parameter estimation and the rate of dynamical evolution of quantum states. We show how both the enhanced accuracy...
From Linear Optical Quantum Computing to Heisenberg-Limited Interferometry (2003)
Lee, Hwang, Kok, Pieter, Williams, Colin P., Dowling, Jonathan P.
The working principles of linear optical quantum computing are based on photodetection, namely, projective measurements. The use of photodetection can provide efficient nonlinear interactions between...
Towards photostatistics from photon-number discriminating detectors (2003)
Lee, Hwang, Yurtsever, Ulvi H., Kok, Pieter, Hockney, George M., Adami, Christoph, Braunstein, Samuel L., ...
We study the properties of a photodetector that has a number-resolving capability. In the absence of dark counts, due to its finite quantum efficiency, photodetection with such a detector can only...
Gravitational decoherence (2003)
We investigate the effect of quantum metric fluctuations on qubits that are gravitationally coupled to a background spacetime. In our first example, we study the propagation of a qubit in flat...
Quantum Imaging and Metrology (2003)
Lee, Hwang, Kok, Pieter, Dowling, Jonathan P.
The manipulation of quantum entanglement has found enormous potential for improving performances of devices such as gyroscopes, clocks, and even computers. Similar improvements have been demonstrated...
An All Linear Optical Quantum Memory Based on Quantum Error Correction (2003)
Gingrich, Robert M., Kok, Pieter, Lee, Hwang, Vatan, Farrokh, Dowling, Jonathan P.
When photons are sent through a fiber as part of a quantum communication protocol, the error that is most difficult to correct is photon loss. Here, we propose and analyze a two-to-four qubit...
Conditional linear-optical measurement schemes generate effective photon nonlinearities (2003)
Lapaire, G. G., Kok, Pieter, Dowling, Jonathan P., Sipe, J. E.
We provide a general approach for the analysis of optical state evolution under conditional measurement schemes, and identify the necessary and sufficient conditions for such schemes to simulate...
Limitations on building single-photon-resolution detection devices (2003)
Single-photon resolution (SPR) detectors can tell the difference between incoming wave packets of n and n+1 photons. Such devices are especially important for linear optical quantum computing with...
Suitability versus fidelity for rating single-photon guns (2002)
Hockney, George M., Kok, Pieter, Dowling, Jonathan P.
The creation of specified quantum states is important for most, if not all, applications in quantum computation and communication. The quality of the state preparation is therefore an essential...
Distributed entanglement as a probe for the quantum structure of spacetime (2002)
Kok, Pieter, Yurtsever, Ulvi, Braunstein, Samuel L., Dowling, Jonathan P.
Simultaneity is a well-defined notion in special relativity once a Minkowski metric structure is fixed on the spacetime continuum (manifold) of events. In quantum gravity, however, the metric is not...
Practical quantum repeaters with linear optics and double-photon guns (2002)
Kok, Pieter, Williams, Colin P., Dowling, Jonathan P.
We show how to create practical, efficient, quantum repeaters, employing double-photon guns, for long-distance optical quantum communication. The guns create polarization-entangled photon pairs on...
A Quantum Rosetta Stone for Interferometry (2002)
Lee, Hwang, Kok, Pieter, Dowling, Jonathan P.
Heisenberg-limited measurement protocols can be used to gain an increase in measurement precision over classical protocols. Such measurements can be implemented using, e.g., optical Mach-Zehnder...
Kok, Pieter, Lee, Hwang, Dowling, Jonathan P.
Optical quantum nondemolition devices can provide essential tools for quantum information processing. Here, we describe several optical interferometers that signal the presence of a single photon in...
Properties of multi-partite dark states (2002)
Kok, Pieter, Nemoto, Kae, Munro, William J.
We investigate and define dark and semi-dark states for multiple qudit systems. For two-level systems, semi-dark and dark states are equivalent. We show that the semi-dark states are equivalent to...
The creation of large photon-number path entanglement conditioned on photodetection (2001)
Kok, Pieter, Lee, Hwang, Dowling, Jonathan P.
Large photon-number path entanglement is an important resource for enhanced precision measurements and quantum imaging. We present a general constructive protocol to create any large photon number...
Lee, Hwang, Kok, Pieter, Cerf, Nicolas J., Dowling, Jonathan P.
We propose a method for preparing maximal path entanglement with a definite photon number N, larger than two, using projective measurements. In contrast with the previously known schemes, our method...
State Preparation in Quantum Optics (2001)
In quantum information and communication, optical schemes provide simple and intuitive experimental implementations. Of particular importance is quantum state preparation. In this thesis, the...
Thesis (Ph. D.) -- University of Wales Bangor (School of Informatics), 2001.
Multi-dimensional Hermite polynomials in quantum optics (2001)
Pieter Kok, Samuel L Braunstein
We study a class of optical circuits with vacuum input states consisting of Gaussian sources without coherent displacements such as down-converters and squeezers, together with photo-detectors and...
Multi-Dimensional Hermite Polynomials in Quantum Optics (2000)
Kok, Pieter, Braunstein, Samuel L
We study a class of optical circuits with vacuum input states consisting of Gaussian sources without coherent displacements such as down-converters and squeezers, together with detectors and passive...
Quantum interferometric optical lithography:towards arbitrary two-dimensional patterns (2000)
Kok, Pieter, Boto, Agedi N., Abrams, Daniel S., Williams, Colin P., Braunstein, Samuel L., Dowling, Jonathan P.
As demonstrated by Boto et al. [Phys. Rev. Lett. 85, 2733 (2000)], quantum lithography offers an increase in resolution below the diffraction limit. Here, we generalize this procedure in order to...
Limitations on the Creation of Maximal Entanglement (2000)
Kok, Pieter, Braunstein, Samuel L
We study a limited set of optical circuits for creating near maximal polarisation entanglement {\em without} the usual large vacuum contribution. The optical circuits we consider involve passive...
Boto, Agedi N., Kok, Pieter, Abrams, Daniel S., Braunstein, Samuel L., Williams, Colin P., Dowling, Jonathan P.
Classical, interferometric, optical lithography is diffraction limited to writing features of a size lambda/2 or greater, where lambda is the optical wavelength. Using nonclassical photon number...
Detection devices in entanglement-based optical state preparation (1999)
Kok, Pieter, Braunstein, Samuel L.
We study the use of detection devices in entanglement-based state preparation. In particular we consider optical detection devices such as single-photon sensitivity detectors, single-photon...
Comment on `Experimental Entanglement Swapping: Entangling Photons That Never Interacted' (1999)
Kok, Pieter, Braunstein, Samuel L.
We comment on the experimental realisation of entanglement swapping by Pan et al. [Phys. Rev. Lett. 80, 3891 (1998)].
Postselected versus nonpostselected quantum teleportation using parametric down-conversion (1999)
Kok, Pieter, Braunstein, Samuel L.
We study the experimental realisation of quantum teleportation as performed by Bouwmeester {\em et al}. [Nature {\bf 390}, 575 (1997)] and the adjustments to it suggested by Braunstein and Kimble...