# Gaussian cloning of coherent states with known phases

## Abstract

The fidelity for cloning coherent states is improved over that provided by optimal Gaussian and non-Gaussian cloners for the subset of coherent states that are prepared with known phases. Gaussian quantum cloning duplicates all coherent states with an optimal fidelity of 2/3. Non-Gaussian cloners give optimal single-clone fidelity for a symmetric 1-to-2 cloner of 0.6826. Coherent states that have known phases can be cloned with a fidelity of 4/5. The latter is realized by a combination of two beam splitters and a four-wave mixer operated in the nonlinear regime, all of which are realized by interaction Hamiltonians that are quadratic in the photon operators. Therefore, the known Gaussian devices for cloning coherent states are extended when cloning coherent states with known phases by considering a nonbalanced beam splitter at the input side of the amplifier.

- Authors:

- Department of Physics and Physical Oceanography, University of North Carolina at Wilmington, Wilmington, North Carolina 28403 (United States)

- Publication Date:

- OSTI Identifier:
- 20787177

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.73.045801; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 74 ATOMIC AND MOLECULAR PHYSICS; AMPLIFIERS; ANNIHILATION OPERATORS; BEAM SPLITTING; CLONING; EIGENSTATES; ENERGY LEVELS; HAMILTONIANS; NONLINEAR PROBLEMS; OPTICS; PHOTONS; QUANTUM COMPUTERS

### Citation Formats

```
Alexanian, Moorad.
```*Gaussian cloning of coherent states with known phases*. United States: N. p., 2006.
Web. doi:10.1103/PHYSREVA.73.0.

```
Alexanian, Moorad.
```*Gaussian cloning of coherent states with known phases*. United States. doi:10.1103/PHYSREVA.73.0.

```
Alexanian, Moorad. Sat .
"Gaussian cloning of coherent states with known phases". United States.
doi:10.1103/PHYSREVA.73.0.
```

```
@article{osti_20787177,
```

title = {Gaussian cloning of coherent states with known phases},

author = {Alexanian, Moorad},

abstractNote = {The fidelity for cloning coherent states is improved over that provided by optimal Gaussian and non-Gaussian cloners for the subset of coherent states that are prepared with known phases. Gaussian quantum cloning duplicates all coherent states with an optimal fidelity of 2/3. Non-Gaussian cloners give optimal single-clone fidelity for a symmetric 1-to-2 cloner of 0.6826. Coherent states that have known phases can be cloned with a fidelity of 4/5. The latter is realized by a combination of two beam splitters and a four-wave mixer operated in the nonlinear regime, all of which are realized by interaction Hamiltonians that are quadratic in the photon operators. Therefore, the known Gaussian devices for cloning coherent states are extended when cloning coherent states with known phases by considering a nonbalanced beam splitter at the input side of the amplifier.},

doi = {10.1103/PHYSREVA.73.0},

journal = {Physical Review. A},

number = 4,

volume = 73,

place = {United States},

year = {Sat Apr 15 00:00:00 EDT 2006},

month = {Sat Apr 15 00:00:00 EDT 2006}

}