We consider the multi-qubit fixed-excitation state transfer along the spin chain with dipole-dipole interaction subjected to the interaction with environment governed by the Lindblad equation preserving the excitation number during spin-evolution. The state transfer algorithm includes the state restoring via Kraus operators and ancilla measurement. As a result, the transferred state appears in superposition with completely mixed state, the latter disappears with vanishing interaction with environment. In that case we deal with probabilistic perfect state transfer. Example of an arbitrary multi-qubit one-excitation state transfer is present and its robustness with respect to perturbation of the Kraus operators is studied.We consider the multi-qubit fixed-excitation state transfer along the spin chain with dipole-dipole interaction subjected to the interaction with environment governed by the Lindblad equation preserving the excitation number during spin-evolution. The state transfer algorithm includes the state restoring via Kraus operators and ancilla measurement. As a result, the transferred state appears in superposition with completely mixed state, the latter disappears with vanishing interaction with environment. In that case we deal with probabilistic perfect state transfer. Example of an arbitrary multi-qubit one-excitation state transfer is present and its robustness with respect to perturbation of the Kraus operators is studied.

quant-pharXiv:2605.13051May 14, 20260 citations

Visualizing Kraus operators for dephasing noise during application of the $\sqrt{\mathrm{\mathrm{SWAP}}}$ quantum gateVisualizing Kraus operators for dephasing noise during application of the $\sqrt{\mathrm{\mathrm{SWAP}}}$ quantum gate

Nicolas André da Costa Morazotti, Reginaldo de Jesus Napolitano

We consider the case of a $\sqrt{\mathrm{SWAP}}$ quantum gate and its optimized entangling action, via continuous dynamical decoupling, in the presence of dephasing noise. We illustrate the procedure in the specific case where only the two-qubit operation is controlled and no single-qubit operations are included in the description. To compare the optimized dynamics in the presence of noise with the ideal case, we use the standard fidelity measure. Then we discuss the importance of using optimized gates in the quantum operational-probabilistic theory. Because of their importance for the explicit construction of the completely positive maps representing the operations, we derive optimized Kraus operators in this specific case, focusing on the entanglement operation. We then show how to visualize the time evolution of each Kraus operator as a curve in a three-dimensional Euclidean space. Finally, we connect this formalism with the operational framework of quantum mechanics by describing a possible set of measurements that could be performed to obtain the Kraus operators.We consider the case of a $\sqrt{\mathrm{SWAP}}$ quantum gate and its optimized entangling action, via continuous dynamical decoupling, in the presence of dephasing noise. We illustrate the procedure in the specific case where only the two-qubit operation is controlled and no single-qubit operations are included in the description. To compare the optimized dynamics in the presence of noise with the ideal case, we use the standard fidelity measure. Then we discuss the importance of using optimized gates in the quantum operational-probabilistic theory. Because of their importance for the explicit construction of the completely positive maps representing the operations, we derive optimized Kraus operators in this specific case, focusing on the entanglement operation. We then show how to visualize the time evolution of each Kraus operator as a curve in a three-dimensional Euclidean space. Finally, we connect this formalism with the operational framework of quantum mechanics by describing a possible set of measurements that could be performed to obtain the Kraus operators.

arXiv:2103.10375Mar 18, 20210 citations

Decoherence and entanglement of a pair of coupled qubits

Mohammad Mehdi Sahrapour, Nancy Makri

Bulletin of the American Physical SocietyMar 23, 20110 citations

Visualizing Kraus operators for dephasing noise during application of the

\sqrt{\mathrm{\mathrm{SWAP}}}

quantum gate

We consider the case of a

\sqrt{\mathrm{SWAP}}

quantum gate and its optimized entangling action, via continuous dynamical decoupling, in the presence of dephasing noise. We illustrate the procedure in the specific case where only the two-qubit operation is controlled and no single-qubit operations are included in the description. To compare the optimized dynamics in the presence of noise with the ideal case, we use the standard fidelity measure. Then we discuss the importance of using optimized gates in the quantum operational-probabilistic theory. Because of their importance for the explicit construction of the completely positive maps representing the operations, we derive optimized Kraus operators in this specific case, focusing on the entanglement operation. We then show how to visualize the time evolution of each Kraus operator as a curve in a three-dimensional Euclidean space. Finally, we connect this formalism with the operational framework of quantum mechanics by describing a possible set of measurements that could be performed to obtain the Kraus operators.