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1.
We propose a scheme for controllably implementing an N-qubit phase gate by one step within a ground-state subspace of N three-state atoms trapped in a cavity through a double Raman passage.We can extend our scheme to the realisation of an arbitrary N-qubit phase gate by appropriately adjusting coupling strengths and detunings between atoms and external driving fields.The advantage of this one-step scheme is its robustness against decoherence. 相似文献
2.
Two simple schemes for implementing Toffoli gate via atom--cavity field interaction in cavity quantum electrodynamics 下载免费PDF全文
This paper proposes two schemes for implementing three-qubit Toffoli
gate with an atom (as target qubit) sent through a two-mode cavity
(as control qubits). The first scheme is based on the large-detuning
atom--cavity field interaction and the second scheme is based on the
resonant atom-field interaction. Both the situations with and
without cavity decay and atomic spontaneous emission are considered.
The advantages and the experimental feasibility of these two schemes
are discussed. 相似文献
3.
本文讨论同时囚禁于单模、大失谐腔场中两个不同原子构成的系统,结论指出:只要仔细选择两不同原子的跃迁频率差、原子与腔场相互作用时间,可实现一个快速的量子相位门。这一方案不需要辅助的原子能级。 相似文献
4.
Scheme for teleportation of an unknown atomic state via a cluster state in cavity QED 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper proposes an experimentally feasible scheme for teleportation of an unknown two-atom entangled state, where a cluster state is used as the quantum channel. This scheme does not need any joint measurement. In addition, the successful probability and fidelity of teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology. 相似文献
5.
This paper proposes an experimentally feasible scheme for
teleportation of an unknown two-atom entangled state, where a
cluster state is used as the quantum channel. This scheme does not
need any joint measurement. In addition, the successful probability
and fidelity of teleportation can both reach 1.0. The current scheme
can be realized within the current experimental technology. 相似文献
6.
CAO Zhuo-Liang LI Da-Chuang 《理论物理通讯》2008,49(2):369-372
An experimentally feasible scheme for teleportation of an unknown two-atom entangled state is proposed. Our scheme uses a duster state as the quantum channel, where we do not need any joint Bell-state measurement. Moreover the successful probability and fidelity of teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology. 相似文献
7.
This paper proposes a scheme for realization of a three-qubit
Toffoli gate operation using three four-level atoms by a selective
atom--field interaction in a cavity quantum electrodynamics system. In
the proposed protocol, the quantum information is encoded on the
stable ground states of atoms, and atomic spontaneous emission is
negligible as the large atom--cavity detuning effectively suppresses
the spontaneous decay of the atoms. The influence of the dissipation
on fidelity and success probability of the three-qubit Toffoli gate
is also discussed. The scheme can also be applied to realize an
N-qubit Toffoli gate and the interaction time required does not
rise with increasing the number of qubits. 相似文献
8.
Generation of multi-atom cluster states via an unconventional geometric phase shift in cavity QED 下载免费PDF全文
This paper proposes two schemes to generate the multi-atom cluster states. The
first scheme is based on the interaction of atoms with a highly
detuned cavity mode and a classical field, the second scheme is
based on the interaction of atoms with a cavity mode, strongly
driven by a resonant classical field. 相似文献
9.
In this paper, we propose a physical scheme to realize quantum SWAP
gate by using a large-detuned single-mode cavity field and two
identical Rydberg atoms. It is shown that the scheme can also be used
to create multi-atom cluster state. During the interaction between
atom and cavity, the cavity is only virtually excited and thus the
scheme is insensitive to the cavity field states and cavity decay.
With the help of our scheme it is very simple to prepare the $N$-atom
cluster state with perfect fidelity and probability. The practical
feasibility of this method is also discussed. 相似文献
10.
In this paper, we propose a physical scheme to realize quantum SWAP gate by using a large-detuned single-mode cavity field and two identical Rydberg atoms. It is shown that the scheme can also be used to create multi-atom cluster state. During the interaction between atom and cavity, the cavity is only virtually excited and thus the scheme is insensitive to the cavity field states and cavity decay. With the help of our scheme it is very simple to prepare the N-atom cluster state with perfect fidelity and probability. The practical feasibility of this method is also discussed. 相似文献
11.
We propose a scheme to implement two-qubit controlled quantum phase
gate(CQPG) via a single trapped two-level ion located
in the standing wave field of a quantum cavity, in which the trap works
beyond the Lamb--Dicke limit.
When the
light field is resonant with the atomic transition
$|g\rangle\leftrightarrow|e\rangle$ of the ion located at the
antinode of the standing wave, we can perform CQPG between the
internal and external states of the trapped ion; while the frequency
of the light field is chosen to be resonant with the first red
sideband of the collective vibrational mode of the ion located at
the node of the standing wave, we can perform CQPG between the
cavity mode and the collective vibrational mode of the trapped ion.
Neither the Lamb--Dicke approximation nor the assistant classical
laser is needed. Also we can generate a GHZ state if assisted with
a classical laser. 相似文献
12.
Implementation of quantum controlled phase gate and preparation of multiparticle entanglement in cavity QED 下载免费PDF全文
Schemes are presented for realizing quantum controlled phase gate and preparing an N-qubit W-like state, which are based on the large-detuned interaction among three-state atoms, dual-mode cavity and a classical pulse. In particular, a class of W states that can be used for perfect teleportation and superdense coding is generated by only one step. Compared with the previous schemes, cavity decay is largely suppressed because the cavity is only virtually excited and always in the vacuum state and the atomic spontaneous emission is strongly restrained due to a large atom-field detuning. 相似文献
13.
Based on two atoms and two cavities initially in two pairs of atom-photon nonmaximally entangled states, we propose a relatively simple scheme to create maximally entangled photon-photon and atom-photon states via entanglement swapping using techniques of cavity QED inspired by the scheme proposed in [Phys. Rev. A 71 (2005)044302] and [Phys. Rev. A 71 (2005) 034312]. Our scheme does not involve the measurement in Bell basis, we only require detecting the states of atoms. 相似文献
14.
A scheme for conditional quantum phase gate viabimodal cavity and a Λ-type three-level atom 下载免费PDF全文
We propose a scheme to implement a two-qubit conditional quantum
phase gatefor the intracavity field viaa single three-level
$\Lambda$-type atom driven by two modes in a high-Q cavity. The
quantum information is encoded on the Fock states of the bimodal
cavity. The gate's averaged fidelity is expected to reach $99.8\%$. 相似文献
15.
16.
WU Zhen-Zhen FANG Mao-Fa JIANG Chun-Lei 《理论物理通讯》2006,46(3):553-555
Based on two atoms and two cavities initially in two pairs of atom-photon nonmaximally entangled states, we propose a relatively simple scheme to create maximally entangled photon-photon and atom-photon states via entanglement swapping using techniques of cavity QED inspired by the scheme proposed in [Phys. Rev. A 71 (2005) 044302] and [Phys. Rev. A 71 (2005) 034312]. Our scheme does not involve the measurement in Bell basis, we only require detecting the states of atoms. 相似文献
17.
A very simpJe theoretical scheme is proposed to implement two-and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. In the presented protocol, the quantum information is encoded on the stable ground states of the atoms (as the controlling qubits) and the zero- and one-photon Fock states of cavity-field (as the target qubit). Under the influence of the atomic spontaneous emission, the decay of the cavity-mode, and deviation of the coupling strength, the three-qubit controlled- phase gate may have a comparatively high fidelity. The experimental feasibility of controlled-phase gate and the ease that is extended to realize N-qubit controlled-phase gate are also discussed. 相似文献
18.
In this paper, we investigate perfect quantum teleportation and dense coding by using an 2N-qubit W state channel. In the quantum teleportation scheme, an unknown N-qubit entangled state can be perfectly teleported. One ebit of entanglement and two bits of classical communication are consumed in the teleportation process, just like when using the Bell state channel. While N+1 bits of classical information can be transmitted by only sending N particles in the dense coding protocol. 相似文献
19.
We propose an efficient scheme to implement a multiplex-controlled phase gate with multiple photonic qubits simultaneously controlling one target photonic qubit based on circuit quantum electrodynamics (QED). For convenience, we denote this multiqubit gate as MCP gate. The gate is realized by using a two-level coupler to couple multiple cavities. The coupler here is a superconducting qubit. This scheme is simple because the gate implementation requires only one step of operation. In addition, this scheme is quite general because the two logic states of each photonic qubit can be encoded with a vacuum state and an arbitrary non-vacuum state |φ> (e.g., a Fock state, a superposition of Fock states, a cat state, or a coherent state, etc.) which is orthogonal or quasi-orthogonal to the vacuum state. The scheme has some additional advantages: because only two levels of the coupler are used, i.e., no auxiliary levels are utilized, decoherence from higher energy levels of the coupler is avoided; the gate operation time does not depend on the number of qubits; and the gate is implemented deterministically because no measurement is applied. As an example, we numerically analyze the circuit-QED based experimental feasibility of implementing a three-qubit MCP gate with photonic qubits each encoded via a vacuum state and a cat state. The scheme can be applied to accomplish the same task in a wide range of physical system, which consists of multiple microwave or optical cavities coupled to a two-level coupler such as a natural or artificial atom. 相似文献
20.
You-Ji Fan Zhen-Fei Zheng Yu Zhang Dao-Ming Lu Chui-Ping Yang 《Frontiers of Physics》2019,14(2):21602
We propose a single-step implementation of a muti-target-qubit controlled phase gate with one catstate qubit (cqubit) simultaneously controlling n–1 target cqubits. The two logic states of a cqubit are represented by two orthogonal cat states of a single cavity mode. In this proposal, the gate is implemented with n microwave cavities coupled to a superconducting transmon qutrit. Because the qutrit remains in the ground state during the gate operation, decoherence caused due to the qutrit’s energy relaxation and dephasing is greatly suppressed. The gate implementation is quite simple because only a single-step operation is needed and neither classical pulse nor measurement is required. Numerical simulations demonstrate that high-fidelity realization of a controlled phase gate with one cqubit simultaneously controlling two target cqubits is feasible with present circuit QED technology. This proposal can be extended to a wide range of physical systems to realize the proposed gate, such as multiple microwave or optical cavities coupled to a natural or artificial three-level atom. 相似文献