We propose a scheme to purify entanglement of two atoms from not-too-impure entangled states by checking the parity of the two atoms through the cavity input-output process.As the parity check is made by measurement o...We propose a scheme to purify entanglement of two atoms from not-too-impure entangled states by checking the parity of the two atoms through the cavity input-output process.As the parity check is made by measurement on single-photon polarization,which would not affect the entanglement of the two atoms,our scheme has the successful probability double of that in a previous well-known scheme with linear optical elements [Nature (London)410 (2001) 1067],and is insensitive to the photon loss and the detection inefficiency.Experimental feasibility of our scheme with current technology is discussed.展开更多
Superpositional wave function oscillations for the implementation of quantum algorithms modify the desired interference required for the quantum computation. We propose a scheme with trapped ultracold ion-pairs being ...Superpositional wave function oscillations for the implementation of quantum algorithms modify the desired interference required for the quantum computation. We propose a scheme with trapped ultracold ion-pairs being qubits to diminish the detrimental effect of the wave function oscillations, which is applied to the two-qubit Grover's search. It can be also found that the qubits in our scheme are more robust against the decoherence caused by the environment, and the model is scalable.展开更多
A scheme is presented for realizing quantum logic gate in an ion trap.In the scheme the state of the mth ion is Grst replicated onto the collective motion.Then a transformation,conditional on the motional state,is per...A scheme is presented for realizing quantum logic gate in an ion trap.In the scheme the state of the mth ion is Grst replicated onto the collective motion.Then a transformation,conditional on the motional state,is performed on the nth ion.Finally the motional state is replicated back onto the mth ion.By this way the quantum logic gate between the mth and the nth ions is realized.The scheme does not put any requirement on the Lamb-Dicke parameter.展开更多
The Schrödinger equation of two ultracold ions confined in xy plane of the Penning trap is exactly solved and the analytical form of the wave function of the system is obtained.A numerical calculation for a conti...The Schrödinger equation of two ultracold ions confined in xy plane of the Penning trap is exactly solved and the analytical form of the wave function of the system is obtained.A numerical calculation for a continued fraction presents the relation among the beigenenergies,the Coulomb interaction and the azimuthal number.展开更多
Taking two identical ions in a Paul trap,we solved the SchrÖdinger equation for one-,two-,and three-dimensional harmonically bound two-body Coulomb models,in which the eigenfunctions are written in a series form ...Taking two identical ions in a Paul trap,we solved the SchrÖdinger equation for one-,two-,and three-dimensional harmonically bound two-body Coulomb models,in which the eigenfunctions are written in a series form and the eigenenergies are obtained from a continued fraction.Numerical calculations are made for specific discussion of two-and three-dimensional case.The comparison with a former one-dimensional approximate work shows that our result is more general and accurate.展开更多
The energy levels and the E2 transition probabilities B(E2)of uranium isotopes ^(230-238)U are calculated by the 1/N expansion technique with the consistent Q framework in sdIBMl.The energy spectra for the five isotop...The energy levels and the E2 transition probabilities B(E2)of uranium isotopes ^(230-238)U are calculated by the 1/N expansion technique with the consistent Q framework in sdIBMl.The energy spectra for the five isotopes and B(E2)of ^(236)U can be reproduced quite well with a few number of parameters only.展开更多
A scheme of teleportation of two unknown quantum states via quantum computation is proposed.The comparison with the former proposals shows that our scheme is more in tune with the original teleportation proposal and t...A scheme of teleportation of two unknown quantum states via quantum computation is proposed.The comparison with the former proposals shows that our scheme is more in tune with the original teleportation proposal and the efficiency is higher.The teleportation of an unknown entangled state is also discussed.展开更多
The pulse sequences of the logic operations used in quantum discrete Fourier transform are designed for the experiment of nuclear magnetic resonance(NMR), and 2-qubit discrete Fourier transforms are implemented experi...The pulse sequences of the logic operations used in quantum discrete Fourier transform are designed for the experiment of nuclear magnetic resonance(NMR), and 2-qubit discrete Fourier transforms are implemented experimentally with NMR. The experimental errors are examined and methods for reducing the errors are proposed.展开更多
The motional trembling(‘zitterbewegung’)of a relativistic electron governed by Dirac equation was originally predicted by Schr¨odinger in the early days of quantum mechanics and simulated in a recent experiment...The motional trembling(‘zitterbewegung’)of a relativistic electron governed by Dirac equation was originally predicted by Schr¨odinger in the early days of quantum mechanics and simulated in a recent experiment with a single trapped ultracold ion.We investigate stable and instable confinements of a single trapped ion in a Paul trap under different conditions relevant to parity.Since our treatment involves neither restriction of Lamb-Dicke limit nor rotating-wave approximation,we may demonstrate different quantum dynamics of the single trapped ion in a wide range of the trapping parameters.We discuss the origin of the zitterbewegung which is relevant to the stability of the ion trapping.展开更多
A cloud of 40Ca+is successfully trapped and cooled using the radiation of a red-detuned 397 nm laser beam and a resonant 866 nm laser beam in our prototype linear ion trap,which was designed and constructed for studyi...A cloud of 40Ca+is successfully trapped and cooled using the radiation of a red-detuned 397 nm laser beam and a resonant 866 nm laser beam in our prototype linear ion trap,which was designed and constructed for studying quantum information processing.We have characterized the size of the ion cloud,estimating the temperature to be in the order of milli-Kelvins.展开更多
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10474118 and 10274093 and the National Fundamental Research Program of China under Grant No. 2005CB724502
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10474118 and 10274093, the National Fundamental Research Program of China under Grant No. 2005CB724502, and the Foundation from Educational Department of Sichuan Province of China under Grant No. 2004C017
基金supported by National Natural Science Foundation of China under Grant Nos.10774163,10774042,and 10747167the State Key Basic Research Program of China under Grant Nos.2005CB724502 and 2006CB921203
文摘We propose a scheme to purify entanglement of two atoms from not-too-impure entangled states by checking the parity of the two atoms through the cavity input-output process.As the parity check is made by measurement on single-photon polarization,which would not affect the entanglement of the two atoms,our scheme has the successful probability double of that in a previous well-known scheme with linear optical elements [Nature (London)410 (2001) 1067],and is insensitive to the photon loss and the detection inefficiency.Experimental feasibility of our scheme with current technology is discussed.
基金Supported by the National Natural Science Foundation of China under Grant No.19904013.
文摘Superpositional wave function oscillations for the implementation of quantum algorithms modify the desired interference required for the quantum computation. We propose a scheme with trapped ultracold ion-pairs being qubits to diminish the detrimental effect of the wave function oscillations, which is applied to the two-qubit Grover's search. It can be also found that the qubits in our scheme are more robust against the decoherence caused by the environment, and the model is scalable.
基金Supported by the National Natural Science Foundation of China under Grant No.19734060.
文摘A scheme is presented for realizing quantum logic gate in an ion trap.In the scheme the state of the mth ion is Grst replicated onto the collective motion.Then a transformation,conditional on the motional state,is performed on the nth ion.Finally the motional state is replicated back onto the mth ion.By this way the quantum logic gate between the mth and the nth ions is realized.The scheme does not put any requirement on the Lamb-Dicke parameter.
基金Supported by the National Natural Science Foundation of China under Grant No.19604013.
文摘The Schrödinger equation of two ultracold ions confined in xy plane of the Penning trap is exactly solved and the analytical form of the wave function of the system is obtained.A numerical calculation for a continued fraction presents the relation among the beigenenergies,the Coulomb interaction and the azimuthal number.
基金Supported by the National Natural Science Foundation of China under Grant No.19404004。
文摘Taking two identical ions in a Paul trap,we solved the SchrÖdinger equation for one-,two-,and three-dimensional harmonically bound two-body Coulomb models,in which the eigenfunctions are written in a series form and the eigenenergies are obtained from a continued fraction.Numerical calculations are made for specific discussion of two-and three-dimensional case.The comparison with a former one-dimensional approximate work shows that our result is more general and accurate.
基金Supported by the National Natural Science Foundation of China。
文摘The energy levels and the E2 transition probabilities B(E2)of uranium isotopes ^(230-238)U are calculated by the 1/N expansion technique with the consistent Q framework in sdIBMl.The energy spectra for the five isotopes and B(E2)of ^(236)U can be reproduced quite well with a few number of parameters only.
基金Supported partly by the National Natural Science Foundation of China under Grant No.19734060,and the special support for the fundamental research by National Commit tee of Science and Technology of China.
文摘A scheme of teleportation of two unknown quantum states via quantum computation is proposed.The comparison with the former proposals shows that our scheme is more in tune with the original teleportation proposal and the efficiency is higher.The teleportation of an unknown entangled state is also discussed.
文摘The pulse sequences of the logic operations used in quantum discrete Fourier transform are designed for the experiment of nuclear magnetic resonance(NMR), and 2-qubit discrete Fourier transforms are implemented experimentally with NMR. The experimental errors are examined and methods for reducing the errors are proposed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11274352 and 11274351)
文摘The motional trembling(‘zitterbewegung’)of a relativistic electron governed by Dirac equation was originally predicted by Schr¨odinger in the early days of quantum mechanics and simulated in a recent experiment with a single trapped ultracold ion.We investigate stable and instable confinements of a single trapped ion in a Paul trap under different conditions relevant to parity.Since our treatment involves neither restriction of Lamb-Dicke limit nor rotating-wave approximation,we may demonstrate different quantum dynamics of the single trapped ion in a wide range of the trapping parameters.We discuss the origin of the zitterbewegung which is relevant to the stability of the ion trapping.
基金supported by the National Natural Science Foundation of China(10774163,10974225)the National Basic Research Program of China(2006CB921203)
文摘A cloud of 40Ca+is successfully trapped and cooled using the radiation of a red-detuned 397 nm laser beam and a resonant 866 nm laser beam in our prototype linear ion trap,which was designed and constructed for studying quantum information processing.We have characterized the size of the ion cloud,estimating the temperature to be in the order of milli-Kelvins.
