# Continuously decoupling single-qubit operations from a perturbing thermal bath of scalar bosons

## Abstract

We investigate the use of continuously applied external fields to maximize the fidelity of quantum logic operations performed on a decohering qubit. Assuming a known error operator and an environment represented by a scalar boson field at a finite temperature, we show how decoherence during logical operations can be efficiently reduced by applying a superposition of two external vector fields: one rotating orthogonally to the direction of the other, which remains static. The required field directions, frequency of rotation, and amplitudes to decouple noise dynamically are determined by the coupling constants and the desired logical operation. We illustrate these findings numerically for a Hadamard quantum gate and an environment with ohmic spectral density.

- Authors:

- Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Caixa Postal 369, 13560-970, Sao Carlos, SP (Brazil)

- Publication Date:

- OSTI Identifier:
- 20982096

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.75.022329; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLITUDES; BOSONS; DECOUPLING; NUMERICAL ANALYSIS; QUANTUM COMPUTERS; QUANTUM MECHANICS; QUBITS; ROTATION; SPECTRAL DENSITY

### Citation Formats

```
Fanchini, F. F., Hornos, J. E. M., and Napolitano, R. d. J..
```*Continuously decoupling single-qubit operations from a perturbing thermal bath of scalar bosons*. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVA.75.022329.

```
Fanchini, F. F., Hornos, J. E. M., & Napolitano, R. d. J..
```*Continuously decoupling single-qubit operations from a perturbing thermal bath of scalar bosons*. United States. doi:10.1103/PHYSREVA.75.022329.

```
Fanchini, F. F., Hornos, J. E. M., and Napolitano, R. d. J.. Thu .
"Continuously decoupling single-qubit operations from a perturbing thermal bath of scalar bosons". United States.
doi:10.1103/PHYSREVA.75.022329.
```

```
@article{osti_20982096,
```

title = {Continuously decoupling single-qubit operations from a perturbing thermal bath of scalar bosons},

author = {Fanchini, F. F. and Hornos, J. E. M. and Napolitano, R. d. J.},

abstractNote = {We investigate the use of continuously applied external fields to maximize the fidelity of quantum logic operations performed on a decohering qubit. Assuming a known error operator and an environment represented by a scalar boson field at a finite temperature, we show how decoherence during logical operations can be efficiently reduced by applying a superposition of two external vector fields: one rotating orthogonally to the direction of the other, which remains static. The required field directions, frequency of rotation, and amplitudes to decouple noise dynamically are determined by the coupling constants and the desired logical operation. We illustrate these findings numerically for a Hadamard quantum gate and an environment with ohmic spectral density.},

doi = {10.1103/PHYSREVA.75.022329},

journal = {Physical Review. A},

number = 2,

volume = 75,

place = {United States},

year = {Thu Feb 15 00:00:00 EST 2007},

month = {Thu Feb 15 00:00:00 EST 2007}

}