dorsal/arxiv
View SchemaDecoherence of two-electron spin states in quantum dots
| Authors | D. D. Bhaktavatsala Rao, V. Ravishankar, V. Subrahmanyam |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0702035 |
| URL | https://arxiv.org/abs/quant-ph/0702035 |
| DOI | 10.1103/PhysRevA.75.052338 |
| Journal | Phys. Rev. A 75, 052338 (2007) |
Abstract
The time evolution of spin states of two electrons interacting with a nuclear spin bath in a quantum dot system is studied. The hyperfine interaction between the electrons and the nuclear spins is modeled by an isotropic Heisenberg interaction, and the interaction between the electron spins by Heisenberg exchange. Depending on the extent of the overlap between the spatial wave functions of the electrons, there are two physically different cases, namely the two qubits either interact with the same set of nuclear spins or they see different nuclear spin environment. In the two cases, the decoherence of the two-qubit state is studied analytically. We have identified a class of two-qubit states which have a rich dynamics when the exchange interaction between the qubits becomes large in comparison to the hyperfine interaction strengths. The decoherence time scale is determined as a function of the bath-spin distribution and the polarizations of the initial two-qubit state. States with large decoherence times are identified by performing a minimization over all the two-qubit pure states.
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"abstract": "The time evolution of spin states of two electrons interacting with a nuclear\nspin bath in a quantum dot system is studied. The hyperfine interaction between\nthe electrons and the nuclear spins is modeled by an isotropic Heisenberg\ninteraction, and the interaction between the electron spins by Heisenberg\nexchange. Depending on the extent of the overlap between the spatial wave\nfunctions of the electrons, there are two physically different cases, namely\nthe two qubits either interact with the same set of nuclear spins or they see\ndifferent nuclear spin environment. In the two cases, the decoherence of the\ntwo-qubit state is studied analytically. We have identified a class of\ntwo-qubit states which have a rich dynamics when the exchange interaction\nbetween the qubits becomes large in comparison to the hyperfine interaction\nstrengths. The decoherence time scale is determined as a function of the\nbath-spin distribution and the polarizations of the initial two-qubit state.\nStates with large decoherence times are identified by performing a minimization\nover all the two-qubit pure states.",
"arxiv_id": "quant-ph/0702035",
"authors": [
"D. D. Bhaktavatsala Rao",
"V. Ravishankar",
"V. Subrahmanyam"
],
"categories": [
"quant-ph",
"cond-mat.mes-hall"
],
"doi": "10.1103/PhysRevA.75.052338",
"journal_ref": "Phys. Rev. A 75, 052338 (2007)",
"title": "Decoherence of two-electron spin states in quantum dots",
"url": "https://arxiv.org/abs/quant-ph/0702035"
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