skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: One-step preparation of cluster states in quantum-dot molecules

Abstract

Cluster states, a special type of highly entangled states, are a universal resource for measurement-based quantum computation. Here, we propose an efficient one-step generation scheme for cluster states in semiconductor quantum dot molecules, where qubits are encoded on singlet and triplet states of two coupled quantum dots. By applying a collective electrical field or simultaneously adjusting interdot bias voltages of all double-dot molecules, we get a switchable Ising-like interaction between any two adjacent quantum molecule qubits. The initialization, the single-qubit measurement, and the experimental parameters are discussed. It is shown that preparation of large cluster states and one-way quantum computation are implementable in semiconductor quantum dots with the present techniques.

Authors:
; ; ;  [1]
  1. Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026 (China)
Publication Date:
OSTI Identifier:
20982433
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevA.75.050301; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ELECTRIC FIELDS; ELECTRIC POTENTIAL; INTERACTIONS; ISING MODEL; MOLECULES; QUANTUM COMPUTERS; QUANTUM DOTS; QUANTUM ENTANGLEMENT; QUBITS; SEMICONDUCTOR MATERIALS; TRIPLETS

Citation Formats

Guo, Guo-Ping, Zhang, Hui, Tu, Tao, and Guo, Guang-Can. One-step preparation of cluster states in quantum-dot molecules. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.050301.
Guo, Guo-Ping, Zhang, Hui, Tu, Tao, & Guo, Guang-Can. One-step preparation of cluster states in quantum-dot molecules. United States. doi:10.1103/PHYSREVA.75.050301.
Guo, Guo-Ping, Zhang, Hui, Tu, Tao, and Guo, Guang-Can. Tue . "One-step preparation of cluster states in quantum-dot molecules". United States. doi:10.1103/PHYSREVA.75.050301.
@article{osti_20982433,
title = {One-step preparation of cluster states in quantum-dot molecules},
author = {Guo, Guo-Ping and Zhang, Hui and Tu, Tao and Guo, Guang-Can},
abstractNote = {Cluster states, a special type of highly entangled states, are a universal resource for measurement-based quantum computation. Here, we propose an efficient one-step generation scheme for cluster states in semiconductor quantum dot molecules, where qubits are encoded on singlet and triplet states of two coupled quantum dots. By applying a collective electrical field or simultaneously adjusting interdot bias voltages of all double-dot molecules, we get a switchable Ising-like interaction between any two adjacent quantum molecule qubits. The initialization, the single-qubit measurement, and the experimental parameters are discussed. It is shown that preparation of large cluster states and one-way quantum computation are implementable in semiconductor quantum dots with the present techniques.},
doi = {10.1103/PHYSREVA.75.050301},
journal = {Physical Review. A},
number = 5,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • Highly entangled states called cluster states are a universal resource for measurement-based quantum computing (QC). Here we propose an efficient method for producing large cluster states using superconducting quantum circuits. We show that a large cluster state can be efficiently generated in just one step by turning on the interqubit coupling for a short time. Because the interqubit coupling is only switched on during the time interval for generating the cluster state, our approach is also convenient for preparing the initial state for each qubit and for implementing one-way QC via single-qubit measurements. Moreover, the cluster state is robust againstmore » parameter variations.« less
  • We present a scalable solid-state system in which the superconducting charge qubits are coupled with a nanomechanical resonator (NAMR) to achieve highly entangled cluster states, which are responsible for one-way quantum computing via single-qubit measurements. Since the NAMR can play the essential role of the data bus, the long-range interactions among the qubits can occur. Therefore, without using the interacting picture we can directly obtain the long-range Ising-like unitary operator U{sub z}({lambda})=exp[i{lambda}S{sub z}{sup 2}] with S{sub z} the collective spin operator in z direction and {lambda} a parameter, which is insensitive to the thermal state of the NAMR. Based onmore » this unitary operator, a set of highly entangled cluster states can be produced by efficient one-step generation. Moreover, the robustness of the highly entangled cluster states with respect to unavoidable parameter variations is also demonstrated.« less
  • The electrical characteristics of metal-oxide-semiconductor (MOS) structures with silicon nanoparticles embedded in silicon oxide have been studied. The nanocrystals are formed by decomposition of an oversaturated solid solution of implanted silicon during thermal annealing at a temperature of {approx}1000 deg. C. At liquid-nitrogen temperature, a stepped current-voltage characteristic is observed in a MOS structure consisting of Si nanocrystals in a SiO{sub 2} film. The stepped current-voltage characteristic is, for the first time, quantitatively described using a model in which charge transport occurs via a chain of local states containing a silicon nanocrystal. The presence of steps is found to bemore » associated with one-electron charging of the silicon nanocrystal and Coulomb blockade of the probability of a hop from the nearest local state to the conducting chain. The local states in silicon dioxide are assumed to be related to an excess of silicon atoms. The presence of such states is confirmed by measurements of the differential conductance and capacitance. For MOS structures implanted with silicon, the differential capacitance and conductance are found to be higher, compared to the reference structures, in the range of biases exceeding 0.2 V. In the same bias range, the conductance is observed to decrease under ultraviolet irradiation due to a change in the population of the states in the conductivity chains.« less
  • We propose schemes to create cluster states and W states by many superconducting quantum-interference-device qubits in cavities under the influence of the cavity decay. Our schemes do not require auxiliary qubits, and the excited levels are only virtually coupled throughout the scheme, which could much reduce the experimental challenge. We consider the cavity decay in our model and analytically demonstrate its detrimental influence on the prepared entangled states.