Research Repository

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Generating multimode entangled microwaves with a superconducting parametric cavity (2018)
Journal Article
Chang, C. S., Simoen, M., Aumentado, J., Sabín, C., Forn-Díaz, P., Vadiraj, A., …Wilson, C. (2018). Generating multimode entangled microwaves with a superconducting parametric cavity. Physical Review Applied, 10(4), doi:10.1103/PhysRevApplied.10.044019

We demonstrate the generation of multimode entangled states of propagating microwaves. The entangled states are generated by our parametrically pumping a multimode superconducting cavity. By combining different pump frequencies, applied simultaneousl... Read More

Analogue simulation of gravitational waves in a 3+1-dimensional Bose-Einstein condensate (2018)
Journal Article
Hartley, D., Bravo, T., Rätzel, D., Howl, R., & Fuentes, I. (2018). Analogue simulation of gravitational waves in a 3+1-dimensional Bose-Einstein condensate. Physical Review D, 98(2), doi:10.1103/physrevd.98.025011

The recent detections of gravitational waves (GWs) by the LIGO and Virgo collaborations have opened the field of GW astronomy, intensifying interest in GWs and other possible detectors sensitive in different frequency ranges. Although strong GW produ... Read More

Frequency spectrum of an optical resonator in a curved spacetime (2018)
Journal Article
Rätzel, D., Schneiter, F., Braun, D., Bravo, T., Howl, R., Lock, M. P., & Fuentes, I. (2018). Frequency spectrum of an optical resonator in a curved spacetime. New Journal of Physics, 20(5), doi:10.1088/1367-2630/aac0ac

The effect of gravity and proper acceleration on the frequency spectrum of an optical resonator—both rigid or deformable—is considered in the framework of general relativity. The optical resonator is modeled either as a rod of matter connecting two m... Read More

Quantum decoherence of phonons in Bose–Einstein condensates (2017)
Journal Article
Howl, R., Sabín, C., Hackermüller, L., & Fuentes, I. (2017). Quantum decoherence of phonons in Bose–Einstein condensates. Journal of Physics B: Atomic, Molecular and Optical Physics, 51(1), doi:10.1088/1361-6455/aa9622. ISSN 0953-4075

We apply modern techniques from quantum optics and quantum information science to Bose–Einstein condensates(BECs)in order to study, for the first time, the quantum decoherence of phonons of isolated BECs. In the last few years, major advances in the... Read More

Relativistic Quantum Clocks (2017)
Book Chapter
Lock, M. P. E., & Fuentes, I. (2017). Relativistic Quantum Clocks. In Time in Physics: Tutorials, Schools, and Workshops in the Mathematical Sciences, 51-68. Springer. doi:10.1007/978-3-319-68655-4_5

The conflict between quantum theory and the theory of relativity is exemplified in their treatment of time. We examine the ways in which their conceptions differ, and describe a semiclassical clock model combining elements of both theories. The resul... Read More

Experimental test of photonic entanglement in accelerated reference frames (2017)
Journal Article
Fink, M., Rodriguez-Aramendia, A., Handsteiner, J., Ziarkash, A., Steinlechner, F., Scheidl, T., …Ursin, R. (2017). Experimental test of photonic entanglement in accelerated reference frames. Nature Communications, 8, 1-6. doi:10.1038/ncomms15304

The unification of the theory of relativity and quantum mechanics is a long-standing challenge in contemporary physics. Experimental techniques in quantum optics have only recently reached the maturity required for the investigation of quantum system... Read More

Quantum communications and quantum metrology in the spacetime of a rotating planet (2017)
Journal Article
Kohlrus, J., Bruschi, D. E., Louko, J., & Fuentes, I. (2017). Quantum communications and quantum metrology in the spacetime of a rotating planet. EPJ Quantum Technology, 4, doi:10.1140/epjqt/s40507-017-0061-0. ISSN 2196-0763

We study how quantum systems that propagate in the spacetime of a rotating planet are affected by the curved background. Spacetime curvature affects wavepackets of photons propagating from Earth to a satellite, and the changes in the wavepacket encod... Read More

Optimal probe states for the estimation of Gaussian unitary channels (2016)
Journal Article
Šafránek, D., & Fuentes, I. (2016). Optimal probe states for the estimation of Gaussian unitary channels. Physical Review A, 94(6), doi:10.1103/physreva.94.062313

We construct a practical method for finding optimal Gaussian probe states for the estimation of parameters encoded by Gaussian unitary channels. This method can be used for finding all optimal probe states, rather than focusing on the performance of... Read More

Thermal noise in BEC-phononic gravitational wave detectors (2016)
Journal Article
Sabín, C., Kohlrus, J., Bruschi, D. E., & Fuentes, I. (2016). Thermal noise in BEC-phononic gravitational wave detectors. EPJ Quantum Technology, 3(1), doi:10.1140/epjqt/s40507-016-0046-4

Quasiparticles in a Bose-Einstein condensate are sensitive to space-time distortions. Gravitational waves can induce transformations on the state of phonons that can be observed through quantum state discrimination techniques. We show that this metho... Read More

Towards universal quantum computation through relativistic motion (2016)
Journal Article
Bruschi, D. E., Sabín, C., Kok, P., Johansson, G., Delsing, P., & Fuentes, I. (2016). Towards universal quantum computation through relativistic motion. Scientific Reports, 6, doi:10.1038/srep18349

We show how to use relativistic motion to generate continuous variable Gaussian cluster states within cavity modes. Our results can be demonstrated experimentally using superconducting circuits where tuneable boundary conditions correspond to mirrors... Read More

Generating entanglement between two-dimensional cavities in uniform acceleration (2016)
Journal Article
Regula, B., Lee, A. R., Dragan, A., & Fuentes, I. (2016). Generating entanglement between two-dimensional cavities in uniform acceleration. Physical Review D, 93(2), doi:10.1103/physrevd.93.025034

Moving cavities promise to be a suitable system for relativistic quantum information processing. It has been shown that an inertial and a uniformly accelerated one-dimensional cavity can become entangled by letting an atom emit an excitation while it... Read More

Quantum thermodynamics for a model of an expanding Universe (2016)
Journal Article
Nana Liu, , Goold, J., Fuentes, I., Vedral, V., Modi, K., & Bruschi, D. E. (2016). Quantum thermodynamics for a model of an expanding Universe. Classical and Quantum Gravity, 33(3), 035003. doi:10.1088/0264-9381/33/3/035003

We investigate the thermodynamical properties of quantum fields in curved spacetime. Our approach is to consider quantum fields in curved spacetime as a quantum system undergoing an out-of-equilibrium transformation. The non-equilibrium features are... Read More