Engineering topics

Pingxing, Chen

Publications and source records attributed to Pingxing, Chen.

3 records

DOE OSTI2011

Realization of universal adiabatic quantum computation with fewer physical resources

The adiabatic quantum computation (AQC) has been proved to be equivalent with the standard circuit model. To realize AQC, we have to realize the target Hamiltonian. However, usually the target Hamiltonian contains k-local terms where k{>=}3 which is difficult to realize in experiment. It has been proved that a k-local Hamiltonian can be reduced to a two-local one. However, the reduction process needs a lot of auxiliary qubits which makes the system very complicated. Here we show that one can reduce a three-local Hamiltonian to a two-local one using only one third of the auxiliary qubits the previous approach needs and, in special cases, only three auxiliary qubits.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2011

Quantum phase transition of light in a one-dimensional photon-hopping-controllable resonator array

We give a concrete experimental scheme for engineering the insulator-superfluid transition of light in a one-dimensional (1D) array of coupled superconducting stripline resonators. In our proposed architecture, the on-site interaction and the photon-hopping rate can be tuned independently by adjusting the transition frequencies of the charge qubits inside the resonators and at the resonator junctions, respectively, which permits us to systematically study the quantum phase transition of light in a complete parameter space. By combining the techniques of photon-number-dependent qubit transition and fast readout of the qubit state using a separate low-Q resonator mode, the statistical property of the excitations in each resonator can be obtained with a high efficiency. An analysis of the various decoherence sources and disorders shows that our scheme can serve as a guide to upcoming experiments involving a small number of coupled resonators.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2010

Experimental study on discretely modulated continuous-variable quantum key distribution

We present a discretely modulated continuous-variable quantum key distribution system in free space by using strong coherent states. The amplitude noise in the laser source is suppressed to the shot-noise limit by using a mode cleaner combined with a frequency shift technique. Also, it is proven that the phase noise in the source has no impact on the final secret key rate. In order to increase the encoding rate, we use broadband homodyne detectors and the no-switching protocol. In a realistic model, we establish a secret key rate of 46.8 kbits/s against collective attacks at an encoding rate of 10 MHz for a 90% channel loss when the modulation variance is optimal.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗