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# Optical control of one and two hole spins in interacting quantum dots

## Abstract

A single hole spin in a semiconductor quantum dot has emerged as a quantum bit that is potentially superior to an electron spin. A key feature of holes is that they have a greatly reduced hyperfine interaction with nuclear spins, which is one of the biggest difficulties in working with an electron spin. It is now essential to show that holes are viable for quantum information processing by demonstrating fast quantum gates and scalability. To this end, we have developed InAs/GaAs quantum dots coupled through coherent tunnelling and charged with controlled numbers of holes. We report fast, single-qubit gates using a sequence of short laser pulses. We then take the important next step towards scalability of quantum information by optically controlling two interacting hole spins in separate dots.

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## Acknowledgements

This work was supported by a Multi-University Research Initiative (US Army Research Office; W911NF0910406) and the US Office of Naval Research.

## Author information

Authors

### Contributions

All authors were involved in the conception of the work and in writing the manuscript. A.S.B. grew and processed the samples. A.G., S.G.C. and D.K. performed the optical measurements. A.G., S.G.C. and D.G. performed data analysis and modelling.

### Corresponding author

Correspondence to Daniel Gammon.

## Ethics declarations

### Competing interests

The authors declare no competing financial interests.

## Rights and permissions

Reprints and Permissions

Greilich, A., Carter, S., Kim, D. et al. Optical control of one and two hole spins in interacting quantum dots. Nature Photon 5, 702–708 (2011). https://doi.org/10.1038/nphoton.2011.237

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