A scheme is proposed to implement quantum controlled-not(CNOT) gates with a resonant cavity and this quantum gate is used to carry out teleportation of an arbitrary single-atom superposition state.By using three level atoms,it can be realized through single-qubit operation and resonant interaction between two atoms and a resonant cavity.The interaction time between two atoms and the single-mode cavity is very short,which is important in view of decoherence.This character is one of the advantages of this scheme comparing to the scheme based on detuned cavity.A scheme is proposed to implement quantum controlled-not(CNOT) gates with a resonant cavity and this quantum gate is used to carry out teleportation of an arbitrary single-atom superposition state.By using three level atoms,it can be realized through single-qubit operation and resonant interaction between two atoms and a resonant cavity.The interaction time between two atoms and the single-mode cavity is very short,which is important in view of decoherence.This character is one of the advantages of this scheme comparing to the scheme based on detuned cavity.

Chinese Journal of Quantum ElectronicsJan 1, 20090 citations

Experimental realization of the quantum universal NOT gate

F. De Martini, Vladimír Bužek, Fabio Sciarrino +1 more

NatureOct 1, 2002170 citations

Experimental benchmarking of quantum control in zero-field nuclear magnetic resonance

Min Jiang, Teng Wu, John W. Blanchard +3 more

Zero-field nuclear magnetic resonance (NMR) provides complementary analysis modalities to those of high-field NMR and allows for ultra-high-resolution spectroscopy and measurement of untruncated spin-spin interactions. Unlike for the high-field case, however, universal quantum control -- the ability to perform arbitrary unitary operations -- has not been experimentally demonstrated in zero-field NMR. This is because the Larmor frequency for all spins is identically zero at zero field, making it challenging to individually address different spin species. We realize a composite-pulse technique for arbitrary independent rotations of $^1$ H and $^{13}$ C spins in a two-spin system. Quantum-information-inspired randomized benchmarking and state tomography are used to evaluate the quality of the control. We experimentally demonstrate single-spin control for $^{13}$ C with an average gate fidelity of $0.9960(2)$ and two-spin control via a controlled-not (CNOT) gate with an estimated fidelity of $0.99$ . The combination of arbitrary single-spin gates and a CNOT gate is sufficient for universal quantum control of the nuclear spin system. The realization of complete spin control in zero-field NMR is an essential step towards applications to quantum simulation, entangled-state-assisted quantum metrology, and zero-field NMR spectroscopy.Zero-field nuclear magnetic resonance (NMR) provides complementary analysis modalities to those of high-field NMR and allows for ultra-high-resolution spectroscopy and measurement of untruncated spin-spin interactions. Unlike for the high-field case, however, universal quantum control -- the ability to perform arbitrary unitary operations -- has not been experimentally demonstrated in zero-field NMR. This is because the Larmor frequency for all spins is identically zero at zero field, making it challenging to individually address different spin species. We realize a composite-pulse technique for arbitrary independent rotations of $^1$H and $^{13}$C spins in a two-spin system. Quantum-information-inspired randomized benchmarking and state tomography are used to evaluate the quality of the control. We experimentally demonstrate single-spin control for $^{13}$C with an average gate fidelity of $0.9960(2)$ and two-spin control via a controlled-not (CNOT) gate with an estimated fidelity of $0.99$. The combination of arbitrary single-spin gates and a CNOT gate is sufficient for universal quantum control of the nuclear spin system. The realization of complete spin control in zero-field NMR is an essential step towards applications to quantum simulation, entangled-state-assisted quantum metrology, and zero-field NMR spectroscopy.

Jan 1, 201828 citations

Natural two-qubit gate for quantum computation using the XY interaction

Norbert Schuch, Jens Siewert

The two-qubit interaction Hamiltonian of a given physical implementation determines whether or not a two-qubit gate such as the controlled-NOT (CNOT) gate can be realized easily. It can be shown that, e.g., with the $\mathrm{XY}$ interaction more than one two-qubit operation is required in order to realize the CNOT operation. Here we propose a two-qubit gate for the $\mathrm{XY}$ interaction which combines the CNOT and SWAP operations. By using this gate quantum circuits can be implemented efficiently, even if only nearest-neighbor coupling between the qubits is available.The two-qubit interaction Hamiltonian of a given physical implementation determines whether or not a two-qubit gate such as the controlled-NOT (CNOT) gate can be realized easily. It can be shown that, e.g., with the $\mathrm{XY}$ interaction more than one two-qubit operation is required in order to realize the CNOT operation. Here we propose a two-qubit gate for the $\mathrm{XY}$ interaction which combines the CNOT and SWAP operations. By using this gate quantum circuits can be implemented efficiently, even if only nearest-neighbor coupling between the qubits is available.

arXiv:quant-ph/0209035Physical Review AMar 10, 2003237 citations

Demonstration of an all-optical quantum controlled-NOT gate

Jeremy L. O’Brien, Geoff J. Pryde, Andrew G. White +2 more

NatureNov 1, 2003992 citations

^1

H and

^{13}

C spins in a two-spin system. Quantum-information-inspired randomized benchmarking and state tomography are used to evaluate the quality of the control. We experimentally demonstrate single-spin control for

^{13}

C with an average gate fidelity of

0.9960(2)

and two-spin control via a controlled-not (CNOT) gate with an estimated fidelity of

0.99

. The combination of arbitrary single-spin gates and a CNOT gate is sufficient for universal quantum control of the nuclear spin system. The realization of complete spin control in zero-field NMR is an essential step towards applications to quantum simulation, entangled-state-assisted quantum metrology, and zero-field NMR spectroscopy.

\mathrm{XY}

interaction more than one two-qubit operation is required in order to realize the CNOT operation. Here we propose a two-qubit gate for the

\mathrm{XY}

interaction which combines the CNOT and SWAP operations. By using this gate quantum circuits can be implemented efficiently, even if only nearest-neighbor coupling between the qubits is available.