Distinguishability of Gaussian States in Quantum Cryptography using Post-Selection (2009)
Weedbrook, Christian, Alton, Daniel J., Symul, Thomas, Lam, Ping Koy, Ralph, Timothy C.
We consider the distinguishability of Gaussian states from the view point of continuous-variable quantum cryptography using post-selection. Specifically, we use the probability of error to...
Observation of entanglement between two light beams spanning an octave in optical frequency (2008)
Grosse, Nicolai B., Assad, Syed, Mehmet, Moritz, Schnabel, Roman, Symul, Thomas, Lam, Ping Koy
We have experimentally demonstrated how two beams of light separated by an octave in frequency can become entangled after their interaction in a second-order nonlinear medium. The entangler consisted...
Observation of Entanglement between Two Light Beams Spanning an Octave in Optical Frequency (2008)
Grosse, Nicolai B., Assad, Syed, Mehmet, Moritz, Schnabel, Roman, Symul, Thomas, Ping, Koy Lam
We have experimentally demonstrated how two beams of light separated by an octave in frequency can become entangled after their interaction in a chi(2) nonlinear medium. The entangler was a nonlinear...
Quantum Cloning of Continuous Variable Entangled States (2007)
Weedbrook, Christian, Grosse, Nicolai B., Symul, Thomas, Lam, Ping Koy, Ralph, Timothy C.
We consider the quantum cloning of continuous variable entangled states. This is achieved by introducing two symmetric entanglement cloning machines (or e-cloners): a local e-cloner and a global...
Symul, Thomas, Alton, Daniel J., Assad, Syed M., Lance, Andrew M., Weedbrook, Christian, Ralph, Timothy C., ...
In realistic continuous variable quantum key distribution protocols, an eavesdropper may exploit the additional Gaussian noise generated during transmission to mask her presence. We present a...
Coherent State Distinguishability in Continuous Variable Quantum Cryptography (2007)
Weedbrook, Christian, Gu, Mile, Lance, Andrew M., Symul, Thomas, Lam, Ping Koy, Ralph, Timothy C.
We use the probability of error as a measure of distinguishability between two pure and two mixed symmetric coherent states in the context of continuous variable quantum cryptography. We show that...
Measuring photon anti-bunching from continuous variable sideband squeezing (2006)
Grosse, Nicolai B., Symul, Thomas, Stobińska, Magdalena, Ralph, Timothy C., Lam, Ping Koy
We present a technique for measuring the second-order coherence function $g^{(2)}(\tau)$ of light using a Hanbury-Brown Twiss intensity interferometer modified for homodyne detection. The experiment...
Conditional quantum-state engineering using ancillary squeezed-vacuum states (2006)
Jeong, Hyunseok, Lance, Andrew M., Grosse, Nicolai B., Symul, Thomas, Lam, Ping Koy, Ralph, Timothy C.
We investigate an optical scheme to conditionally engineer quantum states using a beam splitter, homodyne detection and a squeezed vacuum as an ancillar state. This scheme is efficient in producing...
Quantum State Engineering with Continuous-Variable Post-Selection (2005)
Lance, Andrew M., Jeong, Hyunseok, Grosse, Nicolai B., Symul, Thomas, Ralph, Timothy C., Lam, Ping Koy
We present a scheme to conditionally engineer an optical quantum system via continuous-variable measurements. This scheme yields high-fidelity squeezed single photon and superposition of coherent...
Coherent State Quantum Key Distribution Without Random Basis Switching (2005)
Weedbrook, Christian, Lance, Andrew M., Bowen, Warwick P., Symul, Thomas, Ralph, Timothy C., Lam, Ping Koy
The random switching of measurement bases is commonly assumed to be a necessary step of quantum key distribution protocols. In this paper we show that switching is not required for coherent state...
No-Switching Quantum Key Distribution using Broadband Modulated Coherent Light (2005)
Lance, Andrew M., Symul, Thomas, Sharma, Vikram, Weedbrook, Christian, Ralph, Timothy C., Lam, Ping Koy
We realize an end-to-end no-switching quantum key distribution protocol using continuous-wave coherent light. We encode weak broadband Gaussian modulations onto the amplitude and phase quadratures of...
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...
Quantum Cryptography without Switching (2004)
Weedbrook, Christian, Lance, Andrew M., Bowen, Warwick P., Symul, Thomas, Ralph, Timothy C., Lam, Ping Koy
We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates...
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...
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....
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...
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...
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...
Experimental investigation of continuous variable quantum teleportation (2002)
Bowen, Warwick P., Treps, Nicolas, Buchler, Ben C., Schnabel, Roman, Ralph, Timothy C., Bachor, Hans -A., ...
We report the experimental demonstration of quantum teleportation of the quadrature amplitudes of a light field. Our experiment was stably locked for long periods, and was analyzed in terms of...