Quantum fluctuations of the vacuum are both a surprising and fundamental phenomenon of nature. Understood as virtual photons, they still have a very real impact, for instance, in the Casimir effects and the lifetimes of atoms. Engineering vacuum fluctuations is therefore becoming increasingly important to emerging technologies. Here, we shape vacuum fluctuations using a superconducting circuit analogue of a mirror, creating regions in space where they are suppressed. Moving an artificial atom through these regions and measuring the spontaneous emission lifetime of the atom provides us with the spectral density of the vacuum fluctuations. Using the paradigm of waveguide quantum electrodynamics, we significantly improve over previous studies of the interaction of an atom with its mirror image, observing a spectral density as low as 0.02 quanta, a factor of 50 below the mirrorless result. This demonstrates that we can hide the atom from the vacuum, even though it is exposed in free space.
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Dirac, P. A. M. The quantum theory of the emission and absorption of radiation. Proc. R. Soc. Lond. A 114, 243–265 (1927).
Bethe, H. A. The electromagnetic shift of energy levels. Phys. Rev. 72, 339–341 (1947).
Lamb, W. E. & Retherford, R. C. Fine structure of the hydrogen atom by a microwave method. Phys. Rev. 72, 241–243 (1947).
Schwinger, J. On quantum-electrodynamics and the magnetic moment of the electron. Phys. Rev. 73, 416–417 (1948).
Welton, T. Some observable effects of the quantum-mechanical fluctuation of the electromagnetic field. Phys. Rev. 74, 1157–1167 (1948).
Lamoreaux, S. K. Casimir forces: Still surprising after 60 years. Phys. Today 60, 40–45 (February, 2007).
Harris, D. Harnessing the quantum power of empty space. New Sci. 2852, 34–37 (2012).
Hawking, S. W. Black hole explosions. Nature 248, 30–31 (1974).
Unruh, W. G. Notes on black-hole evaporation. Phys. Rev. D 14, 870–892 (1976).
Casimir, H. B. G. On the attraction between two perfectly conducting plates. Proc. K. Ned. Akad. Wet. B 51, 793–795 (1948).
Moore, G. T. Quantum theory of the electromagnetic field in a variable-length one-dimensional cavity. J. Math. Phys. 11, 2679–2691 (1970).
Wilson, C. M. et al. Observation of the dynamical Casimir effect in a superconducting circuit. Nature 479, 376–379 (2011).
Chan, H. B., Aksyuk, V. A., Kleiman, R. N., Bishop, D. J. & Capasso, F. Quantum mechanical actuation of microelectromechanical systems by the Casimir force. Science 291, 1941–1944 (2001).
Houck, A. A et al. Controlling the spontaneous emission of a superconducting transmon qubit. Phys. Rev. Lett. 101, 080502 (2008).
Astafiev, O., Pashkin, Yu. A., Nakamura, Y., Yamamoto, T. & Tsai, J. S. Quantum noise in the Josephson charge qubit. Phys. Rev. Lett. 93, 267007 (2004).
Eschner, J., Raab, Ch., Schmidt-Kaler, F. & Blatt, R. Light interference from single atoms and their mirror images. Nature 413, 495–498 (2001).
Dorner, U. & Zoller, P. Laser-driven atoms in half-cavities. Phys. Rev. A 66, 023816 (2002).
Bushev, P. et al. Forces between a single atom and its distant mirror image. Phys. Rev. Lett. 92, 223602 (2004).
Dubin, F. et al. Photon correlation versus interference of single-atom fluorescence in a half-cavity. Phys. Rev. Lett. 98, 183003 (2007).
Glaetzle, A. W., Hammerer, K., Daley, A. J., Blatt, R. & Zoller, P. A single trapped atom in front of an oscillating mirror. Opt. Commun. 283, 758–765 (2010).
Purcell, E. M. Spontaneous emission probabilities at radio frequencies. Phys. Rev. 69, 681 (1946).
Kleppner, D. Inhibited spontaneous emission. Phys. Rev. Lett. 47, 233 (1981).
DeMartini, F., Innocenti, G., Jacobovitz, G. R. & Mataloni, P. Anomalous spontaneous emission time in a microscopic optical cavity. Phys. Rev. Lett. 59, 2955–2958 (1987).
Lee, M. Three-dimensional imaging of cavity vacuum with single atoms localized by a nanohole array. Nature Commun. 5, 3441 (2014).
Reed, M.D. et al. Fast reset and surprising spontaneous emission of a superconducting qubit. Appl. Phys. Lett. 96, 203110 (2010).
Kockum, A. F., Delsing, P. & Johansson, G. Designing frequency-dependent relaxation rates and Lamb shifts for a giant artificial atom. Phys. Rev. A 90, 013837 (2014).
van Loo, A. F. et al. Photon-mediated interactions between distant artificial atoms. Science 342, 1494–1496 (2013).
Astafiev, O. et al. Resonance fluorescence of a single artificial atom. Science 327, 840–843 (2010).
Abdumalikov, A. A. et al. Electromagnetically induced transparency on a single artificial atom. Phys. Rev. Lett. 104, 193601 (2010).
Hoi, I.-C. et al. Demonstration of a single-photon router in the microwave regime. Phys. Rev. Lett. 107, 073601 (2011).
Hoi, I.-C. et al. Generation of nonclassical microwave states using an artificial atom in 1d open space. Phys. Rev. Lett. 108, 263601 (2012).
Hoi, I.-C. et al. Giant cross–Kerr effect for propagating microwaves induced by an artificial atom. Phys. Rev. Lett. 111, 053601 (2013).
Hoi, I.-C. et al. Microwave quantum optics with an artificial atom in one-dimensional open space. New J. Phys. 15, 025011 (2013).
Zheng, H., Gauthier, D. J. & Baranger, H. U. Waveguide-QED-based photonic quantum computation. Phys. Rev. Lett. 111, 090502 (2013).
Chang, D. E., Sorensen, A. S., Demler, E. A. & Lukin, M. D. A single-photon transistor using nanoscale surface plasmons. Nature Phys. 3, 807–812 (2007).
Shen, J. T. & Fan, S. H. Coherent single photon transport in a one-dimensional waveguide coupled with superconducting quantum bits. Phys. Rev. Lett. 95, 213001 (2005).
Lalumiere, K. et al. Input–output theory for waveguide QED with an ensemble of inhomogeneous atoms. Phys. Rev. A 88, 043806 (2013).
Koch, J. et al. Charge-insensitive qubit design derived from the Cooper pair box. Phys. Rev. A 76, 042319 (2007).
Clerk, A. A., Devoret, M. H., Girvin, S. M., Marquardt, F. & Schoelkopf, R. J. Introduction to quantum noise, measurement and amplification. Rev. Mod. Phys. 82, 1155–1208 (2010).
Koshino, K. & Nakamura, Y. Control of the radiative level shift and linewidth of a superconducting artificial atom through a variable boundary condition. New J. Phys. 14, 043005 (2012).
Wendin, G. & Shumeiko, V. S. Quantum bits with Josephson junctions. Low Temp. Phys. 33, 724–744 (2007).
Makhlin, Y., Schön, G. & Shnirman, A. Quantum-state engineering with Josephson-junction devices. Rev. Mod. Phys. 73, 357–400 (2001).
Peropadre, B. et al. Scattering of coherent states on a single artificial atom. New J. Phys. 15, 035009 (2013).
We acknowledge financial support from STINT, the Swedish Research Council, the European Union represented by the ERC and the EU project PROMISCE, NSERC of Canada, Industry Canada, and the Government of Ontario. We would also like to acknowledge J. Kimble, G. Milburn, T. Stace, J. M. Martinis, C. P. Sun and H. Dong for fruitful discussions.
The authors declare no competing financial interests.
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Hoi, IC., Kockum, A., Tornberg, L. et al. Probing the quantum vacuum with an artificial atom in front of a mirror. Nature Phys 11, 1045–1049 (2015). https://doi.org/10.1038/nphys3484
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