## Relativistic Quantum Teleportation

Teleportation in space-time

Quantum Teleportation – a concept that is more than an ingenious theoretical proposal, it is even more than a baffling quantum phenomenon that pushed researchers to the development of new technologies.

Accounting for the motion in the teleportation protocol is not only conceptually satisfying, but the effects we describe may lead to the development of new relativistic quantum technologies that help to improve the precision and security of communication for the next generation of quantum technology, see Ref.[1].

*“Teleportation”*is a key word that is familiar to most people from popular television, so familiar, in fact, that researchers adopted the term for the puzzling quantum process, in which a property of a microscopic quantum system is transported to a second, distant quantum object without actually sending or even knowing the corresponding property. As in the fictitious stories that the term teleportation was borrowed from, the senders and receivers of information that is transmitted in this way are generally moving in space and time. In this context one may think of satellites orbiting our planet. Our research concerns the influence of the motion of the involved parties on the success of quantum teleportation. In particular, we are interested in the effects of relativistic motion, that is, objects moving with varying, potentially high speeds, or in the presence of space-time curvature due to gravitation. Using novel mathematical techniques that were developed in our group at the University of Nottingham we are able to give the first complete description of quantum teleportation between moving partners.Accounting for the motion in the teleportation protocol is not only conceptually satisfying, but the effects we describe may lead to the development of new relativistic quantum technologies that help to improve the precision and security of communication for the next generation of quantum technology, see Ref.[1].

## Relativistic Quantum Information

A main goal in the field of relativistic quantum information is to find suitable ways to store and process information using quantum systems in relativistic settings. The vantage point of these investigations is that the world is fundamentally both quantum and relativistic. We hope to be able to find ways of exploiting relativistic resources to improve quantum information tasks such as teleportation and quantum cryptography. We are also interested in using tools developed in quantum information (for example entanglement measures) to address open questions in gravity and cosmology. The information loss problem in black holes is a good example of the usefulness of applying quantum information concepts.

## Relativistic Quantum Metrology

Quantum metrology techniques and quantum geometric phases can be applied to measure physical parameters that play an important role in quantum field theory. For example, using these techniques the Unruh temperature can be measured at accelerations up to a billion times smaller than previous proposals [2]. Moreover, entanglement can be used to determine spacetime parameters such as the expansion rate of the Universe [3].

[1] N. Friis, A. R. Lee, K. Truong, C. Sabín, E. Solano, G. Johansson and I. Fuentes,

[2] M. Aspachs, G. Adesso, & I. Fuentes, "Optimal quantum estimation of the Unruh-Hawking effect, Phys. Rev. Lett. 105, 151301 (2010).

E. Martín-Martínez, I. Fuentes, & R. B. Mann, "Using Berry's phase to detect the Unruh effect at lower accelerations", Phys. Rev. Lett. 107, 131301 (2011).

[3] J. L. Ball, I. Fuentes-Schuller & F. P. Schuller, "Entanglement in an expanding spacetime", Phys. Lett. A,

I. Fuentes, R. B. Mann, E. Martín-Martínez, & S. Moradi, "Entanglement of Dirac fields in an expanding spacetime", Phys. Rev. D

[1] N. Friis, A. R. Lee, K. Truong, C. Sabín, E. Solano, G. Johansson and I. Fuentes,

*"**Relativistic Quantum Teleportation with**Superconducting Circuits"*, Phys. Rev. Lett.**110**, 113602 (2013), e-print arXiv:1211.5563 [quant-ph] (2013).[2] M. Aspachs, G. Adesso, & I. Fuentes, "Optimal quantum estimation of the Unruh-Hawking effect, Phys. Rev. Lett. 105, 151301 (2010).

E. Martín-Martínez, I. Fuentes, & R. B. Mann, "Using Berry's phase to detect the Unruh effect at lower accelerations", Phys. Rev. Lett. 107, 131301 (2011).

[3] J. L. Ball, I. Fuentes-Schuller & F. P. Schuller, "Entanglement in an expanding spacetime", Phys. Lett. A,

**359**, 550 (2006).I. Fuentes, R. B. Mann, E. Martín-Martínez, & S. Moradi, "Entanglement of Dirac fields in an expanding spacetime", Phys. Rev. D

**82**, 045030 (2010).