We study the decoherence of two ferro- and antiferromagnetically coupled spins that interact with a frustrated spin-bath environment in its ground state. The conditions under which the two-spin system relaxes from the initial spin-up--spin-down state toward its ground state are determined. It is shown that the two-spin system relaxes to its ground state for narrow ranges of the model parameters only. It is demonstrated that the symmetry of the coupling between the two-spin system and the environment has an important effect on the relaxation process. In particular, we show that, if this coupling conserves the magnetization, the two-spin system readily relaxes to its ground state, whereas a nonconserving coupling prevents the two-spin system from coming close to its ground state.We study the decoherence of two ferro- and antiferromagnetically coupled spins that interact with a frustrated spin-bath environment in its ground state. The conditions under which the two-spin system relaxes from the initial spin-up--spin-down state toward its ground state are determined. It is shown that the two-spin system relaxes to its ground state for narrow ranges of the model parameters only. It is demonstrated that the symmetry of the coupling between the two-spin system and the environment has an important effect on the relaxation process. In particular, we show that, if this coupling conserves the magnetization, the two-spin system readily relaxes to its ground state, whereas a nonconserving coupling prevents the two-spin system from coming close to its ground state.

arXiv:cond-mat/0701490Physical Review AMay 18, 200720 citations

Nuclear spin $3/2$ electric quadrupole relaxation as a quantum computation processNuclear spin $3/2$ electric quadrupole relaxation as a quantum computation process

Alexandre M. Souza, A. Gavini-Viana, Ivan S. Oliveira +4 more

In this work we applied a quantum circuit treatment to describe the nuclear spin relaxation. From the Redfield theory, we obtain a description of the quadrupolar relaxation as a computational process in a spin 3/2 system, through a model in which the environment is comprised by five qubits and three different quantum noise channels. The interaction between the environment and the spin 3/2 nuclei is described by a quantum circuit fully compatible with the Redfield theory of relaxation. Theoretical predictions are compared to experimental data, a short review of quantum channels and relaxation in NMR qubits is also present.In this work we applied a quantum circuit treatment to describe the nuclear spin relaxation. From the Redfield theory, we obtain a description of the quadrupolar relaxation as a computational process in a spin 3/2 system, through a model in which the environment is comprised by five qubits and three different quantum noise channels. The interaction between the environment and the spin 3/2 nuclei is described by a quantum circuit fully compatible with the Redfield theory of relaxation. Theoretical predictions are compared to experimental data, a short review of quantum channels and relaxation in NMR qubits is also present.

Quantum Information and ComputationJul 1, 20107 citations

Relaxation in a one dimensional spin system

R. W. Gibberd, G.C. Stey

Physics Letters ASep 1, 19713 citations

Relaxation transitions in spin systems

Lieven van Gerven

PhysicaJan 1, 19671 citation

Four-spin cross relaxation in a hybrid quantum device

Cheng Ma, Zhiling Wang, Yukai Wu +4 more

Understanding the spin relaxation in superconducting quantum circuit and solid-state spin hybrid systems is of great importance especially for quantum storage purposes. We have studied the longitudinal relaxation for electron spins of substitutional nitrogen (P1) centers in a hybrid quantum device containing a diamond and a superconducting coplanar waveguide resonator. From a series of pump-probe experiments we conclude that the dominated spin relaxation mechanism is a cross-relaxation process induced by a four-spin interaction (four-spin cross relaxation) among different hyperfine split spin transitions. Some features of the four-spin process are discussed based on a set of rate equations. This work provides interesting perspectives in understanding the coherence properties of the hyperfine split spin ensembles in a hybrid quantum system.Understanding the spin relaxation in superconducting quantum circuit and solid-state spin hybrid systems is of great importance especially for quantum storage purposes. We have studied the longitudinal relaxation for electron spins of substitutional nitrogen (P1) centers in a hybrid quantum device containing a diamond and a superconducting coplanar waveguide resonator. From a series of pump-probe experiments we conclude that the dominated spin relaxation mechanism is a cross-relaxation process induced by a four-spin interaction (four-spin cross relaxation) among different hyperfine split spin transitions. Some features of the four-spin process are discussed based on a set of rate equations. This work provides interesting perspectives in understanding the coherence properties of the hyperfine split spin ensembles in a hybrid quantum system.

Physical Review AJul 16, 20190 citations

Nuclear spin

3/2

electric quadrupole relaxation as a quantum computation process