Low-loss nonlinear polaritonics (2009)
Moiseev, Sergey A., Kamli, Ali A., Sanders, Barry C.
We propose large low-loss cross-phase modulation between two coupled surface polaritons propagating through a double electromagnetically-induced transparency medium situated close to a negative-index...
Dangling-bond charge qubit on a silicon surface (2009)
Livadaru, Lucian, Xue, Peng, Shaterzadeh-Yazdi, Zahra, DiLabio, Gino A., Mutus, Josh, Pitters, Jason L., ...
Two closely spaced dangling bonds positioned on a silicon surface and sharing an excess electron are considered with respect to the DiVincenzo criteria revealing such an entity to be a strong...
Machine Learning for Precise Quantum Measurement (2009)
Hentschel, Alexander, Sanders, Barry C.
Machine learning is an automated process for creating and enhancing algorithms and has had revolutionary impact in data mining and pattern recognition. Quantum information presents a new challenge...
Quantum walk on a line for a trapped ion (2009)
Xue, Peng, Sanders, Barry C., Leibfried, Dietrich
We show that a multi-step quantum walk can be realized for a single trapped ion with interpolation between quantum and random walk achieved by randomizing the generalized Hadamard coin flip phase....
Quantum states prepared by realistic entanglement swapping (2009)
Scherer, Artur, Howard, Gina, Sanders, Barry C., Tittel, Wolfgang
Entanglement swapping between photon pairs is a fundamental building block in schemes using quantum relays or quantum repeaters to overcome the range limits of long distance quantum key distribution....
Kim, Jeong San, Sanders, Barry C.
We prove an analytic positive lower bound for the geometric distance between entangled positive partial transpose (PPT) states of a broad class and any private state that delivers one secure key bit....
A heralded two-qutrit entangled state (2009)
Joo, Jaewoo, Rudolph, Terry, Sanders, Barry C.
We propose a scheme for building a heralded two-qutrit entangled state from polarized photons. An optical circuit is presented to build the maximally entangled two-qutrit state from two heralded Bell...
On continuous variable quantum algorithms for oracle identification problems (2008)
Adcock, Mark, Hoyer, Peter, Sanders, Barry C.
We establish a framework for oracle identification problems in the continuous variable setting, where the stated problem necessarily is the same as in the discrete variable case, and continuous...
Higher Order Decompositions of Ordered Operator Exponentials (2008)
Wiebe, Nathan, Berry, Dominic W., Hoyer, Peter, Sanders, Barry C.
We present a decomposition scheme based on Lie-Trotter-Suzuki product formulae to represent an ordered operator exponential as a product of ordinary operator exponentials. We provide a rigorous proof...
Time reversal frameness and superselection (2008)
Gour, Gilad, Sanders, Barry C., Turner, Peter S.
We show that appropriate superpositions of motional states are a reference frame resource that enables breaking of time-reversal superselection so that two parties lacking knowledge about the other's...
Complete Characterization of Quantum-Optical Processes (2008)
Lobino, Mirko, Korystov, Dmitry, Kupchak, Connor, Figueroa, Eden, Sanders, Barry C., Lvovsky, A. I.
The technologies of quantum information and quantum control are rapidly improving, but full exploitation of their capabilities requires complete characterization and assessment of processes that...
Kim, Jeong San, Das, Anirban, Sanders, Barry C.
We propose replacing concurrence by convex-roof extended negativity (CREN) for studying monogamy of entanglement (MoE). We show that all proven MoE relations using concurrence can be rephrased in...
Graph States for Quantum Secret Sharing (2008)
Markham, Damian, Sanders, Barry C.
We consider three broad classes of quantum secret sharing with and without eavesdropping and show how a graph state formalism unifies otherwise disparate quantum secret sharing models. In addition to...
Generalized W-Class State and its Monogamy Relation (2008)
Kim, Jeong San, Sanders, Barry C.
We generalize the W class of states from $n$ qubits to $n$ qudits and prove that their entanglement is fully characterized by their partial entanglements even for the case of the mixture that...
Coherent control of low loss surface polaritons (2008)
Kamli, Ali, Moiseev, Sergey A., Sanders, Barry C.
We propose fast all-optical control of surface polaritons (SPs) by placing an electromagnetically induced transparency (EIT) medium at an interface between two materials. EIT provides longitudinal...
Tripartite entanglement dynamics for atom in a two-mode nonlinear cavity (2008)
Abdel-Aty, Mahmoud, Abdalla, M. Sebawe, Sanders, Barry C.
In this communication we introduce a new model which represents the interaction between an atom and two fields injected simultaneously within a cavity including the nonlinear couplers. By using the...
Security aspects of practical quantum cryptography (2008)
Gilles Brassard, Norbert Lütkenhaus, Tal Mor, Barry C. Sanders
Abstract. The use of quantum bits (qubits) in cryptography holds the promise of secure cryptographic quantum key distribution schemes. Unfortunately, the implemented schemes are often operated in a...
Beals, Travis R., Sanders, Barry C.
We introduce a simple, practical approach with probabilistic information-theoretic security to mitigate one of quantum key distribution's major limitations: the short maximum transmission distance...
Distributed authentication for randomly compromised networks (2008)
Beals, Travis R., Hynes, Kevin P., Sanders, Barry C.
We introduce a simple, practical approach with probabilistic information-theoretic security to solve one of quantum key distribution's major security weaknesses: the requirement of an authenticated...
Quantum walk on circles in phase space (2008)
We propose a variation of the quantum walk on a circle in phase space by conjoining the Hadamard coin flip with simultaneous displacement of the walker's location in phase space and show that this...
Quantum walks on circles in phase space via superconducting circuit quantum electrodynamics (2008)
Xue, Peng, Sanders, Barry C., Blais, Alexandre, Lalumiere, Kevin
We show how a quantum walk can be implemented for the first time in a quantum quincunx created via superconducting circuit quantum electrodynamics (QED), and how interpolation from quantum to random...
Karasik, Raisa I, Marzlin, Karl-Peter, Sanders, Barry C, Whaley, K. Birgitta
We present a detailed analysis of decoherence free subspaces and develop a rigorous theory that provides necessary and sufficient conditions for dynamically stable decoherence free subspaces. This...
Visualizing a silicon quantum computer (2008)
Sanders, Barry C, Hollenberg, Lloyd C. L., Edmundson, Darran, Edmundson, Andrew
Quantum computation is a fast-growing, multi-disciplinary research field. The purpose of a quantum computer is to execute quantum algorithms that efficiently solve computational problems intractable...
Entangling identical bosons in optical tweezers via exchange interaction (2007)
Babcock, Nathan S., Stock, Rene, Raizen, Mark G., Sanders, Barry C.
We first devise a scheme to perform a universal entangling gate via controlled collisions between pairs of atomic qubits trapped with optical tweezers. Second, we present a modification to this...
Super- and subradiant emission of two-level systems in the near-Dicke limit (2007)
Brooke, Peter G., Marzlin, Karl-Peter, Cresser, James D., Sanders, Barry C.
We analyze the stability of super- and subradiant states in a system of identical two-level atoms in the near-Dicke limit, i.e., when the atoms are very close to each other compared to the wavelength...
SU(1,1) symmetry of multimode squeezed states (2007)
Shaterzadeh-Yazdi, Zahra, Turner, Peter S., Sanders, Barry C.
We show that a class of multimode optical transformations that employ linear optics plus two-mode squeezing can be expressed as SU(1,1) operators. These operations are relevant to state-of-the-art...
Strong terahertz emission from superlattices via Zener tunneling (2007)
Han, Peng, Jin, Kui-juan, Sanders, Barry C., Zhou, Yue-liang, Lu, Hui-bin, Yang, Guo-zhen
We develop a comprehensive, elegant theory to explain terahertz (THz) emission from a superlattice over a wide range of applied electric field,which shows excellent agreement between theory...
On the epistemic view of quantum states (2007)
Skotiniotis, Michael, Roy, Aidan, Sanders, Barry C.
We investigate the strengths and limitations of the Spekkens toy model, which is a local hidden variable model that replicates many important properties of quantum dynamics. First, we present a set...
Karasik, Raisa I., Marzlin, Karl-Peter, Sanders, Barry C., Whaley, K. Birgitta
We present a detailed analysis of decoherence free subspaces and develop a rigorous theory that provides necessary and sufficient conditions for dynamically stable decoherence free subspaces. This...
Multi-particle decoherence free subspaces in extended systems (2007)
Karasik, Raisa I., Marzlin, Karl-Peter, Sanders, Barry C., Whaley, K. Birgitta
We develop a method to determine spatial configurations to realize decoherence-free subspaces for spatially extended multi-particle systems. We have assumed normal reservoir behavior including...
Optimal fingerprinting strategies with one-sided error (2007)
Scott, Andrew James, Walgate, Jonathan, Sanders, Barry C.
Fingerprinting enables two parties to infer whether the messages they hold are the same or different when the cost of communication is high: each message is associated with a smaller fingerprint and...
Optimal fingerprinting strategies with one-sided error (2007)
Scott, Andrew James, Walgate, Jonathan, Sanders, Barry C.
Fingerprinting enables two parties to infer whether the messages they hold are the same or different when the cost of communication is high: each message is associated with a smaller fingerprint and...
Optimal fingerprinting strategies with one-sided error (2007)
Scott, Andrew James, Walgate, Jonathan, Sanders, Barry C.
Fingerprinting enables two parties to infer whether the messages they hold are the same or different when the cost of communication is high: each message is associated with a smaller fingerprint and...
Degradation of a quantum directional reference frame as a random walk (2006)
Bartlett, Stephen D., Rudolph, Terry, Sanders, Barry C., Turner, Peter S.
We investigate if the degradation of a quantum directional reference frame through repeated use can be modeled as a classical direction undergoing a random walk on a sphere. We demonstrate that the...
Duality for monogamy of entanglement (2006)
Bandyopadhyay, Somshubhro, Gour, Gilad, Sanders, Barry C.
We establish duality for monogamy of entanglement: whereas monogamy of entanglement inequalities provide an upper bound for bipartite sharability of entanglement in a multipartite system, we prove...
Non-Gaussian states for continuous variable quantum computation via Gaussian maps (2006)
Ghose, Shohini, Sanders, Barry C.
We investigate non-Gaussian states of light as ancillary inputs for generating nonlinear transformations required for quantum computing with continuous variables. We consider a recent proposal for...
Efficiency limits for linear optical processing of single photons and single-rail qubits (2006)
Berry, Dominic W., Lvovsky, A. I., Sanders, Barry C.
We analyze the problem of increasing the efficiency of single-photon sources or single-rail photonic qubits via linear optical processing and destructive conditional measurements. In contrast to...
Large Cross-Phase Modulation between Slow Co-propagating Weak Pulses in Rb (2006)
Wang, Zeng-Bin, Marzlin, Karl-Peter, Sanders, Barry C.
We propose a scheme to generate double electromagnetically induced transparency and optimal cross-phase modulation for two slow, copropagating pulses with matched group velocities in a single species...
Weily, Andrew R, Esselle, Karu P, Bird, Trevor S, Sanders, Barry C
A high gain antenna made from dual 1-D electromagnetic bandgap (EBG) resonators is described. The combination of dual resonators with an array feed achieves a wide radiation bandwidth, thereby...
Linear array of woodpile EBG sectoral horn antennas (2006)
Weily, Andrew R, Esselle, Karu P, Bird, Trevor S, Sanders, Barry C
A technique is described for creating linear array antennas that conform to the natural stacking sequence of the woodpile electromagnetic bandgap (EBG) material. Each element in the linear array...
No-partial erasure of quantum information (2006)
In complete erasure any arbitrary pure quantum state is transformed to a fixed pure state by irreversible operation. Here we ask if the process of partial erasure of quantum information is possible...
Interconvertibility of single-rail optical qubits (2006)
Berry, Dominic W, Lvovsky, A. I, Sanders, Barry C
We show how to convert between partially coherent superpositions of a single photon with the vacuum by using linear optics and postselection based on homodyne measurements. We introduce a generalized...
Linear array of woodpile EBG sectoral horn antennas (2006)
Weily, Andrew R, Esselle, Karu P, Bird, Trevor S, Sanders, Barry C
A technique is described for creating linear array antennas that conform to the natural stacking sequence of the woodpile electromagnetic bandgap (EBG) material. Each element in the linear array...
Weily, Andrew R, Esselle, Karu P, Bird, Trevor S, Sanders, Barry C
A high gain antenna made from dual 1-D electromagnetic bandgap (EBG) resonators is described. The combination of dual resonators with an array feed achieves a wide radiation bandwidth, thereby...
No-partial erasure of quantum information (2006)
In complete erasure any arbitrary pure quantum state is transformed to a fixed pure state by irreversible operation. Here we ask if the process of partial erasure of quantum information is possible...
Interconvertibility of single-rail optical qubits (2006)
Berry, Dominic W, Lvovsky, A. I, Sanders, Barry C
We show how to convert between partially coherent superpositions of a single photon with the vacuum by using linear optics and postselection based on homodyne measurements. We introduce a generalized...
Interconvertibility of single-rail optical qubits (2006)
Berry, Dominic W, Lvovsky, A. I, Sanders, Barry C
We show how to convert between partially coherent superpositions of a single photon with the vacuum by using linear optics and postselection based on homodyne measurements. We introduce a generalized...
Large cross-phase modulation between slow copropagating weak pulses in ⁸⁷Rb (2006)
Wang, Zeng-Bin, Marzlin, Karl-Peter, Sanders, Barry C
We propose a scheme to generate double electromagnetically induced transparency and optimal cross-phase modulation for two slow, copropagating pulses with matched group velocities in a single species...
Quantum teleportation of composite systems via mixed entangled states (2006)
Bandyopadhyay, Somshubhro, Sanders, Barry C
We analyze quantum teleportation for composite systems, specifically for concatenated teleporation (decomposing a large composite state into smaller states of dimension commensurate with the channel)...
Highly nonclassical photon statistics in parametric down-conversions (2006)
Waks, Edo, Sanders, Barry C, Diamanti, Eleni, Yamamoto, Yoshihisa
We use photon counters to obtain the joint photon-counting statistics from twin-beam nondegenerate parametric down-conversion, and we demonstrate directly, and with no auxiliary assumptions, that...
Efficient quantum algorithms for simulating sparse Hamiltonians (2005)
Berry, Dominic W., Ahokas, Graeme, Cleve, Richard, Sanders, Barry C.
We present an efficient quantum algorithm for simulating the evolution of a sparse Hamiltonian H for a given time t in terms of a procedure for computing the matrix entries of H. In particular, when...
Interconvertibility of single-rail optical qubits (2005)
Berry, Dominic W., Lvovsky, Alexander I., Sanders, Barry C.
We show how to convert between partially coherent superpositions of a single photon with the vacuum using linear optics and postselection based on homodyne measurements. We introduce a generalized...
No approximate complex fermion coherent states (2005)
Tyc, Tomas, Hamilton, Brett, Sanders, Barry C., Oliver, William D.
Whereas boson coherent states with complex parametrization provide an elegant, and intuitive representation, there is no counterpart for fermions using complex parametrization. However, a complex...
Optimal fingerprinting strategies with one-sided error (2005)
Scott, A. J., Walgate, Jonathan, Sanders, Barry C.
Fingerprinting enables two parties to infer whether the messages they hold are the same or different when the cost of communication is high: each message is associated with a smaller fingerprint and...
Deterministic Entanglement of Assistance and Monogamy Constraints (2005)
Gour, Gilad, Meyer, David A., Sanders, Barry C.
Certain quantum information tasks require entanglement of assistance, namely a reduction of a tripartite entangled state to a bipartite entangled state via local measurements. We establish that...
No partial erasure of quantum information (2005)
Pati, Arun K., Sanders, Barry C.
In complete erasure any arbitrary pure quantum state is transformed to a fixed pure state by irreversible operation. Here we ask if the process of partial erasure of quantum information is possible...
Equivalence between two-mode spin squeezed states and pure entangled states with equal spin (2005)
Berry, Dominic W., Sanders, Barry C.
We prove that a pure entangled state of two subsystems with equal spin is equivalent to a two-mode spin-squeezed state under local operations except for a set of bipartite states with measure zero,...
Classical and quantum fingerprinting with shared randomness and one-sided error (2005)
Horn, Rolf T., Scott, A. J., Walgate, Jonathan, Cleve, Richard, Lvovsky, A. I., Sanders, Barry C.
Within the simultaneous message passing model of communication complexity, under a public-coin assumption, we derive the minimum achievable worst-case error probability of a classical fingerprinting...
A planar resonator antenna based on a woodpile EGB material (2005)
Weily, Andrew R, Horvath, Levente, Esselle, Karu P, Sanders, Barry C, Bird, Trevor S
A resonator antenna made from a complex artificial surface and a metallic ground plane is described. The complex surface is realized using a woodpile electromagnetic bandgap (EBG) material, which is...
A planar resonator antenna based on a woodpile EGB material (2005)
Weily, Andrew R, Horvath, Levente, Esselle, Karu P, Sanders, Barry C, Bird, Trevor S
A resonator antenna made from a complex artificial surface and a metallic ground plane is described. The complex surface is realized using a woodpile electromagnetic bandgap (EBG) material, which is...
Classical and quantum fingerprinting with shared randomness and one-sided error (2005)
Rolf T, Horn, Scott, Andrew James, Walgate, Jonathan, Cleve, Richard, Lvovski, A. I., Sanders, Barry C.
Within the simultaneous message passing model of communication complexity, under a public-coin assumption, we derive the minimum achievable worst-case error probability of a classical fingerprinting...
Classical and quantum fingerprinting with shared randomness and one-sided error (2005)
Rolf T, Horn, Scott, Andrew James, Walgate, Jonathan, Cleve, Richard, Lvovski, A. I., Sanders, Barry C.
Within the simultaneous message passing model of communication complexity, under a public-coin assumption, we derive the minimum achievable worst-case error probability of a classical fingerprinting...
Classical and quantum fingerprinting with shared randomness and one-sided error (2005)
Rolf T, Horn, Scott, Andrew James, Walgate, Jonathan, Cleve, Richard, Lvovski, A. I., Sanders, Barry C.
Within the simultaneous message passing model of communication complexity, under a public-coin assumption, we derive the minimum achievable worst-case error probability of a classical fingerprinting...
Continuous Variable Quantum State Sharing via Quantum Disentanglement (2004)
Lance, Andrew M., Symul, Thomas, Bowen, Warwick P., Sanders, Barry C., Tyc, Tomas, Ralph, Timothy C., ...
Quantum state sharing is a protocol where perfect reconstruction of quantum states is achieved with incomplete or partial information in a multi-partite quantum networks. Quantum state sharing allows...
Single-qubit optical quantum fingerprinting (2004)
Horn, Rolf T., Babichev, S. A., Marzlin, Karl-Peter, Lvovsky, A. I., Sanders, Barry C.
We analyze and demonstrate the feasibility and superiority of linear optical single-qubit fingerprinting over its classical counterpart. For one-qubit fingerprinting of two-bit messages, we prepare...
Remote Preparation and Distribution of Bipartite Entangled States (2004)
Gour, Gilad, Sanders, Barry C.
We prove a powerful theorem for tripartite remote entanglement distribution protocols that establishes an upper bound on the amount of entanglement of formation that can be created between two...
Canonical entanglement for two indistinguishable particle (2004)
Wang, Xiao-Guang, Sanders, Barry C.
We determine the degree of entanglement for two indistinguishable particles based on the two-qubit tensor product structure, which is a framework for emphasizing entanglement founded on observational...
Entanglement vs. the quantum-to-classical transition (2004)
Ghose, Shohini, Alsing, Paul M., Sanders, Barry C., Deutsch, Ivan H.
We analyze the quantum-to-classical transition (QCT) for coupled bipartite quantum systems for which the position of one of the two subsystems is continuously monitored. We obtain the surprising...
Geometric phase for an adiabatically evolving open quantum system (2004)
Kamleitner, Ingo, Cresser, James D., Sanders, Barry C.
We derive an elegant solution for a two-level system evolving adiabatically under the influence of a driving field with a time-dependent phase, which includes open system effects such as dephasing...
Entanglement dynamics in chaotic systems (2004)
Ghose, Shohini, Sanders, Barry C.
We study quantum chaos for systems with more than one degree of freedom, for which we present an analysis of the dynamics of entanglement. Our analysis explains the main features of entanglement...
Operational formulation of homodyne detection (2004)
We obtain the standard quadrature-phase positive operator-valued measure (POVM) for homodyne detection directly and rigorously from the POVM for photon counting without directly employing the mean...
Complementarity and quantum walks (2004)
Kendon, Viv, Sanders, Barry C.
We show that quantum walks interpolate between a coherent `wave walk' and a random walk depending on how strongly the walker's coin state is measured; i.e., the quantum walk exhibits the...
Inconsistency in the application of the adiabatic theorem (2004)
Marzlin, Karl-Peter, Sanders, Barry C.
The adiabatic theorem states that an initial eigenstate of a slowly varying Hamiltonian remains close to an instantaneous eigenstate of the Hamiltonian at a later time. We show that a perfunctory...
Post-processing with linear optics for improving the quality of single-photon sources (2004)
Berry, Dominic W., Scheel, Stefan, Myers, Casey R., Sanders, Barry C., Knight, Peter L., Laflamme, Raymond
Triggered single-photon sources produce the vacuum state with non-negligible probability, but produce a much smaller multiphoton component. It is therefore reasonable to approximate the output of...
Tripartite Quantum State Sharing (2004)
Lance, Andrew M., Symul, Thomas, Bowen, Warwick P., Sanders, Barry C., Lam, Ping Koy
We demonstrate a multipartite protocol to securely distribute and reconstruct a quantum state. A secret quantum state is encoded into a tripartite entangled state and distributed to three players. By...
Tripartite Quantum State Sharing (2004)
Lance, Andrew M., Symul, Thomas, Bowen, Warwick P., Sanders, Barry C., Lam, Ping Koy
We demonstrate a multipartite protocol to securely distribute and reconstruct a quantum state. A secret quantum state is encoded into a tripartite entangled state and distributed to three players. By...
Electronic coherence theory (2003)
Bartlett, Stephen D., Sanders, Barry C., Oliver, William D., Yamamoto, Yoshihisa
We withdraw our paper as the factorizability of the correlation functions is unproven.
Entanglement as a signature of quantum chaos (2003)
Wang, Xiaoguang, Ghose, Shohini, Sanders, Barry C, Hu, Bambi
We explore the dynamics of entanglement in classically chaotic systems by considering a multiqubit system that behaves collectively as a spin system obeying the dynamics of the quantum kicked top. In...
Tripartite Quantum State Sharing (2003)
Lance, Andrew M., Symul, Thomas, Bowen, Warwick P., Sanders, Barry C., Lam, Ping Koy
We demonstrate a multipartite protocol to securely distribute and reconstruct a quantum state. A secret quantum state is encoded into a tripartite entangled state and distributed to three players....
On improving single photon sources via linear optics and photodetection (2003)
Berry, Dominic W., Scheel, Stefan, Sanders, Barry C., Knight, Peter L.
In practice, single photons are generated as a mixture of vacuum with a single photon with weights 1-p and p, respectively; here we are concerned with increasing p by directing multiple copies of the...
Direct observation of non-classical photon statistics in parametric downconversion (2003)
Waks, Edo, Diamanti, Eleni, Sanders, Barry C., Bartlett, Stephen D., Yamamoto, Yoshihisa
We employ a high quantum efficiency photon number counter to determine the photon number distribution of the output field from a parametric downconverter. The raw photocount data directly...
Numerical Analysis of the Capacities for Two-Qubit Unitary Operations (2003)
Berry, Dominic W., Sanders, Barry C.
We present numerical results on the capacities of two-qubit unitary operations for creating entanglement and increasing the Holevo information of an ensemble. In all cases tested, the maximum values...
Photon-number superselection and the entangled coherent-state representation (2003)
Sanders, Barry C., Bartlett, Stephen D., Rudolph, Terry, Knight, Peter L.
We introduce the entangled coherent state representation, which provides a powerful technique for efficiently and elegantly describing and analyzing quantum optics sources and detectors while...
Bounds on general entropy measures (2003)
Berry, Dominic W., Sanders, Barry C.
We show how to determine the maximum and minimum possible values of one measure of entropy for a given value of another measure of entropy. These maximum and minimum values are obtained for two...
Relations between bosonic quadrature squeezing and atomic spin squeezing (2003)
Wang, Xiaoguang, Sanders, Barry C.
We study relations between bosonic quadrature squeezing and atomic spin squeezing, and find that the latter reduces to the former in the limit of a large number of atoms for even and odd states. We...
Spin squeezing criterion with local unitary invariance (2003)
Devi, A. R. Usha, Wang, Xiaoguang, Sanders, Barry C
We propose a new spin squeezing criterion for arbitrary multi-qubit states that is invariant under local unitary operations. We find that, for arbitrary pure two-qubit states, spin squeezing is...
Requirement for quantum computation (2003)
Bartlett, Stephen D., Sanders, Barry C.
We identify "proper quantum computation" with computational processes that cannot be efficiently simulated on a classical computer. For optical quantum computation, we establish "no-go" theorems for...
Spin squeezing and pairwise entanglement for symmetric multiqubit states (2003)
Wang, Xiaoguang, Sanders, Barry C.
We show that spin squeezing implies pairwise entanglement for arbitrary symmetric multiqubit states. If the squeezing parameter is less than or equal to 1, we demonstrate a quantitative relation...
Efficient sharing of a continuous-variable quantum secret (2003)
Tyc, Tomas, Rowe, David J., Sanders, Barry C.
We propose an efficient scheme for sharing a continuous variable quantum secret using passive optical interferometry and squeezers: this efficiency is achieved by showing that a maximum of two...
Continuous variable (2,3) threshold quantum secret sharing schemes (2003)
Lance, Andrew M., Symul, Thomas, Bowen, Warwick P., Tyc, Tomas, Sanders, Barry C., Lam, Ping Koy
We present two schemes to perform continuous variable (2, 3) threshold quantum secret sharing (QSS) on the quadrature amplitudes of bright light beams. Both schemes require a pair of entangled light...
Bounds on general entropy measures (2003)
Berry, Dominic W, Sanders, Barry C
We show how to determine the maximum and minimum possible values of one measure of entropy for a given value of another measure of entropy. These maximum and minimum values are obtained for two...
Continuous variable (2,3) threshold quantum secret sharing schemes (2003)
Lance, Andrew M., Symul, Thomas, Bowen, Warwick P., Tyc, Tomas, Sanders, Barry C., Lam, Ping Koy
We present two schemes to perform continuous variable (2, 3) threshold quantum secret sharing (QSS) on the quadrature amplitudes of bright light beams. Both schemes require a pair of entangled light...
Efficient sharing of a continuous-variable quantum secret (2003)
Tyc, Tomáš, Rowe, David J, Sanders, Barry C
We propose an efficient scheme for sharing a continuous-variable quantum secret using passive optical interferometry and squeezers: this efficiency is achieved by showing that a maximum of two...
Quantum gates on hybrid qudits (2003)
Daboul, Jamil, Wang, Xiaoguang, Sanders, Barry C
We introduce quantum hybrid gates that act on qudits of different dimensions. In particular, we develop two representative two-qudit hybrid gates (SUM and SWAP) and many-qudit hybrid Toffoli and...
Requirement for quantum computation (2003)
Bartlett, Stephen D, Sanders, Barry C
We identify 'proper quantum computation' with computational processes that cannot be efficiently simulated on a classical computer. For optical quantum computation, we establish no-go theorems for...
Photon-number superselection and the entangled coherent-state representation (2003)
Sanders, Barry C, Bartlett, Stephen D, Rudolph, Terry, Knight, Peter L
We introduce the entangled coherent-state representation, which provides a powerful technique for efficiently and elegantly describing and analyzing quantum optics sources and detectors while...
Quantum quincunx in cavity quantum electrodynamics (2003)
Sanders, Barry C, Bartlett, Stephen D, Tregenna, Ben, Knight, Peter L
We introduce the quantum quincunx, which physically demonstrates the quantum walk and is analogous to Galton’s quincunx for demonstrating the random walk by employing gravity to draw pellets...
Entanglement gauge and the non-Abelian geometric phase with two photonic qubits (2003)
Marzlin, Karl-Peter, Bartlett, Stephen D, Sanders, Barry C
We introduce the entanglement gauge describing the combined effects of local operations and nonlocal unitary transformations on bipartite quantum systems. The entanglement gauge exploits the...
Spin squeezing and pairwise entanglement for symmetric multiqubit states (2003)
Wang, Xiaoguang, Sanders, Barry C
We show that spin squeezing implies pairwise entanglement for arbitrary symmetric multiqubit states. If the squeezing parameter is less than or equal to 1, we demonstrate a quantitative relation...
Multipartite entangled states in coupled quantum dots and cavity QED (2003)
Wang, Xiaoguang, Feng, Mang, Sanders, Barry C
We investigate the generation of multipartite entangled state in a system of N quantum dots embedded in a microcavity and examine the emergence of genuine multipartite entanglement by three different...
Entangling power and operator entanglement in qudit systems (2003)
Wang, Xiaoguang, Sanders, Barry C, Berry, Dominic
We establish the entangling power of a unitary operator on a general finite-dimensional bipartite quantum system with and without ancillas, and give relations between the entangling power based on...
Optimal remote state preparation (2003)
Berry, Dominic W, Sanders, Barry C
We prove that it is possible to remotely prepare an ensemble of noncommuting mixed states using communication equal to the Holevo information for this ensemble. This remote preparation scheme may be...
Berry, Dominic W, Sanders, Barry C
Two-qubit operations may be characterized by their capacities for communication, both with and without free entanglement, and their capacity for creating entanglement. We establish a set of...
Berry, Dominic W, Sanders, Barry C
Bipartite operations underpin both classical communication and entanglement generation. Using a superposition of classical messages, we show that the capacity of a two-qubit operation for error-free...
Continuous variable (2,3) threshold quantum secret sharing schemes (2003)
Lance, Andrew M, Symul, Thomas, Bowen, Warwick P, Tyc, Tomás, Sanders, Barry C, Lam, Ping Koy
We present two schemes to perform continuous variable (2, 3) threshold quantum secret sharing (QSS) on the quadrature amplitudes of bright light beams. Both schemes require a pair of entangled light...
Entanglement capability of self-inverse Hamiltonian evolution (2003)
Wang, Xiaoguang, Sanders, Barry C
We determine the entanglement capability of a self-inverse Hamiltonian evolution, which reduces to the known result for the Ising Hamiltonian, and identify optimal input states for yielding the...
Relations between bosonic quadrature squeezing and atomic spin squeezing (2003)
Wang, Xiaoguang, Sanders, Barry C
We study relations between bosonic quadrature squeezing and atomic spin squeezing, and find that the latter reduces to the former in the limit of a large number of atoms for even and odd states. We...
Optimal remote state preparation (2003)
Berry, Dominic W, Sanders, Barry C
We prove that it is possible to remotely prepare an ensemble of noncommuting mixed states using communication equal to the Holevo information for this ensemble. This remote preparation scheme may be...
Multipartite entangled states in coupled quantum dots and cavity-QED (2002)
Wang, Xiaoguang, Feng, Mang, Sanders, Barry C
We investigate the generation of multipartite entangled state in a system of N quantum dots embedded in a microcavity and examine the emergence of genuine multipartite entanglement by three different...
Entanglement capability of self-inverse Hamiltonian evolution (2002)
Wang, Xiaoguang, Sanders, Barry C.
We determine the entanglement capability of self-inverse Hamiltonian evolution, which reduces to the known result for Ising Hamiltonian, and identify optimal input states for yielding the maximal...
Quantum gates on hybrid qudits (2002)
Daboul, Jamil, Wang, Xiaoguang, Sanders, Barry C
We introduce quantum hybrid gates that act on qudits of different dimensions. In particular, we develop two representative two-qudit hybrid gates (SUM and SWAP) and many-qudit hybrid Toffoli and...
Entangling power and operator entanglement in qudit systems (2002)
Wang, Xiaoguang, Sanders, Barry C., Berry, Dominic W.
We establish the entangling power of a unitary operator on a general finite-dimensional bipartite quantum system with and without ancillas, and give relations between the entangling power based on...
Superpositions of SU(3) coherent states via a nonlinear evolution (2002)
Nemoto, Kae, Sanders, Barry C.
We show that a nonlinear Hamiltonian evolution can transform an SU(3) coherent state into a superposition of distinct SU(3) coherent states, with a superposition of two SU(2) coherent states...
Efficient classical simulation of measurements in optical quantum information (2002)
Bartlett, Stephen D., Sanders, Barry C.
We present conditions for the efficient simulation of a broad class of optical quantum circuits on a classical machine: this class includes unitary transformations, amplification, noise, and...
Entanglement gauge and the non-Abelian geometric phase with two photonic qubits (2002)
Marzlin, Karl-Peter, Bartlett, Stephen D., Sanders, Barry C.
We introduce the entanglement gauge describing the combined effects of local operations and nonlocal unitary transformations on bipartite quantum systems. The entanglement gauge exploits the...
Optimal Remote State Preparation (2002)
Berry, Dominic W., Sanders, Barry C.
We prove that it is possible to remotely prepare an ensemble of non-commuting mixed states using communication equal to the Holevo information for this ensemble. This remote preparation scheme may be...
From Qubits to Continuous-Variable Quantum Computation (2002)
Sanders, Barry C, Bartlett, Stephen D., De Guise, Hubert
By encoding a qudit in a harmonic oscillator and investigating the d --> infinity limit, we give an entirely new realization of continuous-variable quantum computation. The generalized Pauli group is...
Berry, Dominic W., Sanders, Barry C.
Two-qubit operations may be characterized by their capacities for communication, both with and without free entanglement, and their capacity for creating entanglement. We establish a set of...
Quantum quincunx in cavity quantum electrodynamics (2002)
Sanders, Barry C., Bartlett, Stephen D., Tregenna, Ben, Knight, Peter L.
We introduce the quantum quincunx, which physically demonstrates the quantum walk and is analogous to Galton's quincunx for demonstrating the random walk. In contradistinction to the theoretical...
Berry, Dominic W., Sanders, Barry C.
Bipartite operations underpin both classical communication and entanglement generation. Using a superposition of classical messages, we show that the capacity of a two-qubit operation for error-free...
Photon counting schemes and performance of non-deterministic nonlinear gates in linear optics (2002)
Bartlett, Stephen D., Diamanti, Eleni, Sanders, Barry C., Yamamoto, Yoshihisa
The performance of nondeterministic nonlinear gates in linear optics relies on the photon counting scheme being employed and the efficiencies of the detectors in such schemes. We assess the...
Efficient Classical Simulation of Optical Quantum Circuits (2002)
Bartlett, Stephen D., Sanders, Barry C.
We identify a broad class of physical processes in an optical quantum circuit that can be efficiently simulated on a classical computer: this class includes unitary transformations, amplification,...
Continuous-variable quantum teleportation of entanglement (2002)
Johnson, Tyler J., Bartlett, Stephen D., Sanders, Barry C.
Entangled coherent states can be used to determine the entanglement fidelity for a device that is designed to teleport coherent states. This entanglement fidelity is universal, in that the...
Near-optimal two-mode spin squeezing via feedback (2002)
Berry, Dominic W., Sanders, Barry C.
We propose a feedback scheme for the production of two-mode spin squeezing. We determine a general expression for the optimal feedback, which is also applicable to the case of single-mode spin...
Four-photon interferometry for secure quantum key distribution (2002)
Hariharan, P, Sanders, Barry C
We introduce a quantum key distribution scheme based on four–photon coincidence measurements. This scheme offers a much higher degree of security than current quantum key distribution methods and...
Multipartite entangled coherent states (2002)
Wang, Xiaoguang, Sanders, Barry C
We propose a scheme for generating multipartite entangled coherent states via entanglement swapping, with an example of a physical realization in ion traps. Bipartite entanglement of these...
Near-optimal two-mode spin squeezing via feedback (2002)
Berry, Dominic W, Sanders, Barry C
We propose a feedback scheme for the production of two-mode spin squeezing. We determine a general expression for the optimal feedback, which is also applicable to the case of single-mode spin...
Quantum teleportation and entanglement swapping for spin systems (2002)
Berry, Dominic W, Sanders, Barry C
We analyse quantum teleportation (QT) and entanglement swapping (ES) for spin systems. If the permitted operations are restricted to the Ising interaction, plus local rotations and spin measurements,...
How to share a continuous-variable quantum secret by optical interferometry (2002)
We develop the theory of continuous-variable quantum secret sharing and propose its interferometric realization using passive and active optical elements. In the ideal case of infinite squeezing, a...
Efficient classical simulation of continuous variable quantum information processes (2002)
Bartlett, Stephen D, Sanders, Barry C, Braunstein, Samuel L, Nemoto, Kae
We obtain sufficient conditions for the efficient simulation of a continuous variable quantum algorithm or process on a classical computer. The resulting theorem is an extension of the...
Bartlett, Stephen D, Sanders, Barry C
Although universal continuous-variable quantum computation cannot be achieved via linear optics (including squeezing), homodyne detection, and feed-forward, inclusion of ideal photon-counting...
Efficient classical simulation of optical quantum information circuits (2002)
Bartlett, Stephen D, Sanders, Barry C
We identify a broad class of physical processes in an optical quantum circuit that can be efficiently simulated on a classical computer: this class includes unitary transformations, amplification,...
Quantum encodings in spin systems and harmonic oscillators (2002)
Bartlett, Stephen D, De Guise, Hubert, Sanders, Barry C
We show that higher-dimensional versions of qubits, or qudits, can be encoded into spin systems and into harmonic oscillators, yielding important advantages for quantum computation. Whereas...
Continuous-variable quantum teleportation of entanglement (2002)
Johnson, Tyler J, Bartlett, Stephen D, Sanders, Barry C
Entangled coherent states can be used to determine the entanglement fidelity for a device that is designed to teleport coherent states. This entanglement fidelity is universal in that the calculation...
Comment on "The Quantum State of a Propagating Laser Field" (2001)
Rudolph, Terry, Sanders, Barry C.
We comment on the theoretical quantum state of a propagating laser field proposed by van Enk and Fuchs [quant-ph/0104036, quant-ph/0111157] and clarify that the multimode description of the...
Quantum Teleportation and Entanglement Swapping for Spin Systems (2001)
Berry, Dominic W., Sanders, Barry C.
We analyse quantum teleportation (QT) and entanglement swapping (ES) for spin systems. If the permitted operations are restricted to the Ising interaction, plus local rotations and spin measurements,...
Bartlett, Stephen D., Sanders, Barry C.
Although universal continuous-variable quantum computation cannot be achieved via linear optics (including squeezing), homodyne detection and feed-forward, inclusion of ideal photon counting...
Quantum Encodings in Spin Systems and Harmonic Oscillators (2001)
Bartlett, Stephen D., De Guise, Hubert, Sanders, Barry C.
We show that higher-dimensional versions of qubits, or qudits, can be encoded into spin systems and into harmonic oscillators, yielding important advantages for quantum computation. Whereas...
Efficient Classical Simulation of Continuous Variable Quantum Information Processes (2001)
Bartlett, Stephen D., Sanders, Barry C., Braunstein, Samuel L., Nemoto, Kae
We obtain sufficient conditions for the efficient simulation of a continuous variable quantum algorithm or process on a classical computer. The resulting theorem is an extension of the...
Quantum walks in higher dimensions (2001)
Mackay, Troy D., Bartlett, Stephen D., Stephenson, Leigh T., Sanders, Barry C.
We analyze the quantum walk in higher spatial dimensions and compare classical and quantum spreading as a function of time. Tensor products of Hadamard transformations and the discrete Fourier...
How to share a continuous-variable quantum secret by optical interferometry (2001)
We develop the theory of continuous-variable quantum secret sharing and propose its interferometric realization using passive and active optical elements. In the ideal case of infinite squeezing, a...
Geometric Phase in SU(N) Interferometry (2001)
De Guise, Hubert, Sanders, Barry C., Bartlett, Stephen D., Zhang, Weiping
An interferometric scheme to study Abelian geometric phase shift over the manifold SU(N)/SU(N-1) is presented.
Multipartite entangled coherent states (2001)
Wang, Xiaoguang, Sanders, Barry C.
We propose a scheme for generating multipartite entangled coherent states via entanglement swapping, with an example of a physical realization in ion traps. Bipartite entanglement of these...
Requirement of optical coherence for continuous-variable quantum teleportation (2001)
Rudolph, Terry, Sanders, Barry C.
We show that the sender (Alice) and the receiver (Bob) each require coherent devices in order to achieve unconditional continuous variable quantum teleportation (CVQT), and this requirement cannot be...
Geometric Phase of Three-Level Systems in Interferometry (2001)
Bartlett, Stephen D., Guise, Hubert De, Sanders, Barry C., Zhang, Weiping
Quantum Computation with Harmonic Oscillators (2000)
Bartlett, Stephen D., Sanders, Barry C., Varcoe, Benjamin T. H., De Guise, Hubert
By encoding a qudit in a harmonic oscillator and investigating the infinite limit, we give an entirely new realization of continuous-variable quantum computation. The generalized Pauli group is...
Geometric Phase of Three-level Systems in Interferometry (2000)
Sanders, Barry C., De Guise, Hubert, Bartlett, Stephen D., Zhang, Weiping
We present the first scheme for producing and measuring an Abelian geometric phase shift in a three-level system where states are invariant under a non-Abelian group. In contrast to existing...
Radiating dipoles in photonic crystals (2000)
Busch, Kurt, Vats, Nipun, John, Sajeev, Sanders, Barry C.
The radiation dynamics of a dipole antenna embedded in a Photonic Crystal are modeled by an initially excited harmonic oscillator coupled to a non--Markovian bath of harmonic oscillators representing...
Creation of Skyrmions in a Spinor Bose-Einstein Condensate (2000)
Marzlin, Karl-Peter, Zhang, Weiping, Sanders, Barry C.
We propose a scheme for the creation of skyrmions (coreless vortices) in a Bose-Einstein condensate with hyperfine spin F=1. In this scheme, four traveling-wave laser beams, with Gaussian or...
Entangled SU(2) and SU(1,1) coherent states (2000)
Wang, Xiao-Guang, Sanders, Barry C., Pan, Shao-hua
Entangled SU(2) and SU(1,1) coherent states are developed as superpositions of multiparticle SU(2) and SU(1,1) coherent states. In certain cases, these are coherent states with respect to generalized...
Security Aspects of Practical Quantum Cryptography (1999)
Brassard, Gilles, Lütkenhaus, Norbert, Mor, Tal, Sanders, Barry C.
The use of quantum bits (qubits) in cryptography holds the promise of secure cryptographic quantum key distribution schemes. Unfortunately, the implemented schemes can be totally insecure. We provide...
Quantum cryptography via parametric downconversion (1999)
Brassard, Gilles, Mor, Tal, Sanders, Barry C.
The use of quantum bits (qubits) in cryptography holds the promise of secure cryptographic quantum key distribution schemes. It is based usually on single-photon polarization states. Unfortunately,...
Nonclassical Fields and the Nonlinear Interferometer (1998)
Sanders, Barry C., Rice, Dien A.
We demonstrate several new results for the nonlinear interferometer, which emerge from a formalism which describes in an elegant way the output field of the nonlinear interferometer as two-mode...
Asymmetric double barrier resonant tunneling structures with improved characteristics (1998)
Shi, Jun-jie, Sanders, Barry C., Pan, Shao-hua
We present a self-consistent calculation, based on the global coherent tunnelling model, and show that structural asymmetry of double barrier resonant tunnelling structures significantly modifies the...