It is effective to constitute a hybrid qubit system by taking advantages of different types of qubits to overcome the effects of decoherence and achieve quantum information transport. We find that energy relaxation exists in the process of information exchange bewteen the hybrid qubits. Combining this kind of energy relaxation with the decoherence effects from external environment, quantum information transport of non-disentangled effect can be achieved in phase damping channel if the exchange decay rate and decoherence time satisfy certain constraint relations.It is effective to constitute a hybrid qubit system by taking advantages of different types of qubits to overcome the effects of decoherence and achieve quantum information transport. We find that energy relaxation exists in the process of information exchange bewteen the hybrid qubits. Combining this kind of energy relaxation with the decoherence effects from external environment, quantum information transport of non-disentangled effect can be achieved in phase damping channel if the exchange decay rate and decoherence time satisfy certain constraint relations.

Advanced materials researchSep 18, 20130 citations

Relaxation times in an open interacting two-qubit system

Yonatan Dubi, Massimiliano Di Ventra

In a two-qubit system the coupling with an environment considerably affects the entanglement dynamics, usually leads to the loss of entanglement within a finite time. Since entanglement is a key feature in the application of such systems to quantum information processing, it is highly desirable to find a way to prolonging its lifetime. We present a simple model of an interacting two-qubit system in the presence of a thermal Markovian environment. The qubits are modeled as interacting spin- $1∕2$ particles in a magnetic field and the environment is limited to inducing single spin-flip events. A simple scheme allows us to calculate the relaxation rates for all processes. We show that the relaxation dynamics of the most entangled state exhibit critical slowing down as a function of the magnetic field, where the relaxation rate changes from exponentially small values to finite values in the zero-temperature limit. We study the effect of temperature and magnetic field on all the other relaxation rates and find that they exhibit unusual properties, such as nonmonotonic dependence on temperature and a discontinuity as a function of magnetic field. In addition, a simple scheme to include non-Markovian effects is presented and applied to the two-qubit model. We find that the relaxation rates exhibit a sharp, cusplike resonant structure as a function of the environment memory time, and that for long memory times all the different relaxation rates merge into a single one.In a two-qubit system the coupling with an environment considerably affects the entanglement dynamics, usually leads to the loss of entanglement within a finite time. Since entanglement is a key feature in the application of such systems to quantum information processing, it is highly desirable to find a way to prolonging its lifetime. We present a simple model of an interacting two-qubit system in the presence of a thermal Markovian environment. The qubits are modeled as interacting spin-$1∕2$ particles in a magnetic field and the environment is limited to inducing single spin-flip events. A simple scheme allows us to calculate the relaxation rates for all processes. We show that the relaxation dynamics of the most entangled state exhibit critical slowing down as a function of the magnetic field, where the relaxation rate changes from exponentially small values to finite values in the zero-temperature limit. We study the effect of temperature and magnetic field on all the other relaxation rates and find that they exhibit unusual properties, such as nonmonotonic dependence on temperature and a discontinuity as a function of magnetic field. In addition, a simple scheme to include non-Markovian effects is presented and applied to the two-qubit model. We find that the relaxation rates exhibit a sharp, cusplike resonant structure as a function of the environment memory time, and that for long memory times all the different relaxation rates merge into a single one.

arXiv:0809.3256Physical Review AJan 29, 200920 citations

Dynamics of superconducting qubit relaxation

Malcolm S. Carroll, Sami Rosenblatt, Abhinav Kandala

Bulletin of the American Physical SocietyMar 16, 20210 citations

Relaxation processes in solid-state two-qubit gates

Elisabetta Paladino, Antonio D’Arrigo, Andrea Mastellone +1 more

Physica E Low-dimensional Systems and NanostructuresJun 25, 20095 citations

Effect of the electron-hole exchange interaction on the photon-spin quantum state transfer

Yoshiaki Rikitake, Hiroshi Imamura, Hideo Kosaka

We theoretically analyze the yield and fidelity of the quantum state transfer (QST) from a photon polarization qubit to an electron spin qubit using a spin‐coherent photo‐detector consisting of a semiconductor quantum dot. We use the modified one‐dimensional light‐atom interaction model which includes parameters such as photon‐dot interaction, the tunneling rate of the created hole, the bandwidth of the input photon, and the electron‐hole exchange interaction. The electron‐hole exchange interaction disturbs the electron spin state and thus decreases the fidelity of the QST. We find the optimal conditions in which both a high‐yield and high‐fidelity QST is realized.We theoretically analyze the yield and fidelity of the quantum state transfer (QST) from a photon polarization qubit to an electron spin qubit using a spin‐coherent photo‐detector consisting of a semiconductor quantum dot. We use the modified one‐dimensional light‐atom interaction model which includes parameters such as photon‐dot interaction, the tunneling rate of the created hole, the bandwidth of the input photon, and the electron‐hole exchange interaction. The electron‐hole exchange interaction disturbs the electron spin state and thus decreases the fidelity of the QST. We find the optimal conditions in which both a high‐yield and high‐fidelity QST is realized.

AIP conference proceedingsJan 1, 20070 citations

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particles in a magnetic field and the environment is limited to inducing single spin-flip events. A simple scheme allows us to calculate the relaxation rates for all processes. We show that the relaxation dynamics of the most entangled state exhibit critical slowing down as a function of the magnetic field, where the relaxation rate changes from exponentially small values to finite values in the zero-temperature limit. We study the effect of temperature and magnetic field on all the other relaxation rates and find that they exhibit unusual properties, such as nonmonotonic dependence on temperature and a discontinuity as a function of magnetic field. In addition, a simple scheme to include non-Markovian effects is presented and applied to the two-qubit model. We find that the relaxation rates exhibit a sharp, cusplike resonant structure as a function of the environment memory time, and that for long memory times all the different relaxation rates merge into a single one.