共查询到20条相似文献,搜索用时 546 毫秒
1.
SONG Ming-Yu 《理论物理通讯》2011,56(5):837-844
We proposed an efficient scheme for constructing a quantum controlled phase-shift gate and generating the cluster states with rf superconducting quantum interference devices (SQUIDs) coupled to a microwave cavity through adiabatic evolution of dark eigenstates. During the operation, the spontaneous emission is suppressed since the rf SQUIDs are always in the three lowest flux states. Considering the influence from the cavity decay with achievable
experimental parameters, we numerically analyze the success probability and the fidelity for generating the two-SQUID maximally entangled state and the controlled phase-shift gate by adiabatic passage. 相似文献
2.
We propose a scheme for generating a maximally entangled state of two three-level superconducting quantum interference devices (SQUIDs) by using a quantized cavity field and classical microwave pluses in cavity. In this scheme, no quantum information will be transferred from the SQUIDs to the cavity since the cavity field is only virtually excited. Thus, the cavity decay is suppressed during the entanglement generation. 相似文献
3.
ZHAN Zhi-Ming 《理论物理通讯》2009,51(1):135-138
In this paper, a theoretical scheme is proposed to implement the Deutsch-Jozsa algorithm with SQUIDs (superconducting quantum-interference devices) in cavity via Raman transition. The scheme only requires a quantized cavity field and classical microwave pulses. In this scheme, no transfer of quantum information between the SQUIDs and the cavity is required, the cavity field is only virtually excited and thus the cavity decay is suppressed. 相似文献
4.
Preparation of W State with Superconducting Quantum-Interference Devices in a Cavity via Adiabatic Passage 下载免费PDF全文
We propose an alternative scheme to prepare W state by using superconducting quantum-interference devices (SQUIDs) coupled to a largely-detuned cavity. The present scheme is based on evolution by adiabatic passage, where only by tuning adiabatically the Rabi frequencies of the classical microwave pulses we can obtain the standard W state without measurement or any auxiliary SQUIDs. Thus the procedure is simplified and the scheme can be achieved with very high success probability since the errors in dynamical or geometric ways can be avoided. In addition, the SQUID system and the cavity have no probability of being excited state. Thus decoherence caused by the excited-level spontaneous emission or the cavity decay is suppressed. 相似文献
5.
SONG Ke-Hui ZHOU Zheng-Wei GUO Guang-Can 《理论物理通讯》2006,46(4):631-634
We present a scheme to realize geometric phase-shift gate for two superconducting quantum interference device (SQUID) qubits coupled to a single-mode microwave field. The geometric phase-shift gate operation is performed in two lower flux states, and the excited state [2〉 would not participate in the procedure. The SQUIDs undergo no transitions during the gate operation. Thus, the docoherence due to energy spontaneous emission based on the levels of SQUIDs are suppressed. The gate is insensitive to the cavity decay throughout the operation since the cavity mode is displaced along a circle in the phase space, acquiring a phase conditional upon the two lower flux states of the SQUID qubits, and the cavity mode is still in the original vacuum state. Based on the SQUID qubits interacting with the cavity mode, our proposed approach may open promising prospects for quantum iogic in SQUID-system. 相似文献
6.
Realization of Greenberg-Horne-Zeilinger (GHZ) and W Entangled States with Multiple Superconducting Quantum-Interference Device Qubits in Cavity QED 下载免费PDF全文
An alternative scheme is proposed for generating the Greenberg-Horne-Zeilinger (GHZ) and W types of the entangled states with multiple superconducting quantum-interference device (SQUID) qubits in a single-mode microwave cavity field. In this scheme, there is no transfer of quantum information between the SQUIDs and the cavity, the cavity is always in the vacuum and thus the requirement on the quality of cavity is greatly loosened. In addition, during the process of the generation of the W entangled state, the present method does not involve a real excitation of intermediate levels. Thus, decoherence due to energy relaxation of intermediate levels is minimized. 相似文献
7.
ZHAN Zhi-Ming 《理论物理通讯》2008,49(6):1603-1606
We put forward a simple scheme for one-step realization of
a two-qubit SWAP gate with SQUIDs (superconducting quantum-interference
devices) in cavity QED via Raman transition. In this scheme, the cavity
field is only virtually excited and thus the cavity decay is suppressed. The
SWAP gate is realized by using only two lower flux states of the SQUID system
and the excited state would not be excited. Therefore, the effect of
decoherence caused from the levels of the SQUID system is possibly
minimized. The scheme can also be used to implement the SWAP gate with
atoms. 相似文献
8.
Quantum controlled phase gate and cluster states
generation via two superconducting quantum interference devices in a
cavity 总被引:3,自引:0,他引:3
Z.-Y. Xue G. Zhang P. Dong Y.-M. Yi Z.-L. Cao 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(3):333-336
A scheme for implementing 2-qubit quantum controlled phase gate (QCPG) is proposed with two superconducting quantum interference
devices (SQUIDs) in a cavity. The gate operations are
realized within the two lower flux states of the SQUIDs by using a quantized cavity field and classical microwave pulses.
Our scheme is achieved without any type of measurement, does not use the cavity mode as the data bus and only requires a very
short resonant interaction of the SQUID-cavity system. As an application of the QCPG operation, we also propose a scheme for
generating the cluster
states of many SQUIDs. 相似文献
9.
We present a potential scheme to implement two-qubit quantum phase gates through an unconventional geometric phase shift with two four-level SQUIDs in a cavity. The SQUID qubits undergo no transitions during the gate operation, while the cavity mode is displaced along a circle in the phase space, acquiring a geometric phase depending conditionally upon the SQUIDs’ states. Under certain conditions, the SQUID qubits are disentangled with the cavity mode and the SQUIDs’ states remain in their ground states during the gate operation, thus the gate is insensitive to both the SQUIDs’ “spontaneous emission” and the cavity decay. 相似文献
10.
11.
We propose a scheme for generating the maximally entangled states of many superconducting quantum interference devices (SQUIDs) by using a quantized cavity field and classicalmicrowave pulses in cavity. In the scheme,the maximally entangled states can be generated without requiring the measurement and individual addressing of the SQUIDs. 相似文献
12.
We presented a scheme to implement SWAP gate in a microwave cavity. In our scheme, two superconducting quantum interference
device (SQUID) qubits are coupled to a single-mode microwave cavity field by adiabatic passage method for their manipulation.
This process of implementing SWAP gate is in the range of present experiments. The scheme can be easily obtained only by three
steps, which does not require perform any operation. In the scheme, the operations only involve three lowest flux states of
the SQUIDs, and the excited states would not be excited; therefore, the decoherence due to spontaneous emission of the SQUIDs’
levels would not affect the operations. In addition, during the whole procedure the cavity field is not necessary to be excited
because it does not require transfer quantum information between the SQUID’s and the cavity field. Thus, the cavity decay
is suppressed. Therefore our scheme may be realized in superconducting systems. 相似文献
13.
SONG Ke-Hui ZHOU Zheng-Wei GUO Guang-Can 《理论物理通讯》2006,46(10)
We present a scheme to realize geometric phase-shift gate for two superconducting quantum interference device (SQUID) qubits coupled to a single-mode microwave field. The geometric phase-shift gate operation is performed transitions during the gate operation. Thus, the docoherence due to energy spontaneous emission based on the levels of SQUIDs are suppressed. The gate is insensitive to the cavity decay throughout the operation since the cavity mode is displaced along a circle in the phase space, acquiring a phase conditional upon the two lower flux states of the SQUID qubits, and the cavity mode is still in the original vacuum state. Based on the SQUID qubits interacting with the cavity mode, our proposed approach may open promising prospects for quantum logic in SQUID-system. 相似文献
14.
One-step implementing three-qubit phase gate via manipulating rf SQUID qubits in the decoherence-free subspace with respect to cavity decay 下载免费PDF全文
We present a scheme for implementing a three-qubit phase
gate via manipulating rf superconducting quantum interference device
(SQUID) qubits in the decoherence-free subspace with respect to
cavity decay. Through appropriate changes of the coupling constants
between rf SQUIDs and cavity, the scheme can be realized only in one
step. A high fidelity is obtained even in the presence of
decoherence. 相似文献
15.
本文提出一个方案以通过探测光子的衰减来制备囚禁在一个腔中的若干个原子的W态。在我们的方案中,腔的衰减率远大于原子与腔的耦合强度。这样,对腔品质因子的要求被大大降低。这在实验上是很重要的。本方案的另一个优点是通过拉曼跃迁原子总是处于两个基态,因而原子的自发辐射也被抑制。 相似文献
16.
Scheme for Quantum Entanglement Swapping on Cavity QED System 总被引:1,自引:0,他引:1
We propose a scheme for realizing quantum entanglement swapping
between the atoms in cavity QED. With only virtual excitation of the cavity during the interaction between the atoms and cavity, the scheme is insensitive to the cavity mode states and the cavity decay. The ideas can also be utilized for realizing entanglement swapping between the atomic levels in a single atom and the atomic levels in the Bell states and
between the atomic levels in the Bell states and the atomic
levels in the W states. 相似文献
17.
提出了一步变换三原子W态为三原子超单态的方案。在方案中,三个五能级原子同时与双模腔发生离散相互作用。方案的优点是可以有效抵御原子自发辐射和腔衰变引起的消相干的影响。 相似文献
18.
We propose a scheme to generate a three-qubit three-level singlet state in cavity QED, by placing three Λ-type SQUIDs in a single mode cavity. In this scheme, we make use of the interaction between the SQUIDs and cavity filed, and the classical pulses. The cavity fields are in vacuum state during the whole operation processes of creating the entanglement, and there is no quantum information transformation between the SQUIDs and cavity fields. Because of the advantage of the SQUID-cavity system, the quality factor of the cavity is greatly relaxed. 相似文献
19.
We propose a simple scheme to not only generate GHZ states and W states of the multiparticle but also form a new category of multiparticle entangled states by letting the λ-type three-level atoms simultaneously interacting with a coherent cavity field followed by the selective measurements on the cavity mode. We investigate the influence of the cavity dissipation on the generated entangled state and discuss the experimental feasibility of our scheme. It is shown that the intensity of the coherent cavity field plays an instructive role in contribution to state preparation process while the cavity decay and the detuning between the atoms and cavity mode result in the deterioration of the generated entangled state. 相似文献
20.
A scheme is proposed for generating entangled W states with four
cavity modes. In this scheme, we send a V-type three-level atom
through two identical two-mode cavities in succession. After the
atom exits from the second cavity, the four cavity modes are
prepared in the W state. On the other hand we can obtain
three-atom W states by sending three V-type three-level atoms
through a two-mode cavity in turn. The present scheme does not
require conditional measurement, and it is easily generalized to
preparing $2n$-mode W states and $n$-atom W states. 相似文献