Vollständige Charakterisierung von Quanteneffekten von Licht nach der Transmission durch die Atmosphäre
Zusammenfassung der Projektergebnisse
The topic of the project was the Full Characterization of the Quantum Effects of Light after Transmission through the Atmosphere. In other words, we aimed at the characterization of quantum states of light after the propagation through turbulent freespace channels. For scenarios, the fluctuating losses in these channels which arise from atmospheric turbulence are of major importance and can crucially alter the quantum properties of the sent light. Taken this effect into account, we studied continuousvariable and discrete-variable quantum states, introduced a simulation technique for atmospheric channels, developed general methods to certify quantum correlations from imperfect measurements, and analyzed and optimized the performance of quantum information protocols. For important classes of discrete-variable quantum states we could analytically identify the conditions for which entanglement and other nonclassical features can survive the propagation through atmospheric channels and the influence of other noise sources. In this context, we analyzed two important classes of discrete-variable states, N00N and Werner states, and generalized them to more general noisy states. In particular, we could demonstrate that entanglement quasiprobabilities and tailored witnesses are an excellent method for the certification of entanglement in such noisy discrete-variable systems. For continuous-variable states suffering from atmospheric losses, we provided a complete and rigorous treatment of the important class of entangled two-mode Gaussian states. We demonstrated that new physical effects occur in such free-space channels and that adaptive channel correlations can lead to a conservation of entanglement in such channels. We generalized this treatment to general nonclassicality and entanglement criteria based on the input-output relations for single and multi-mode matrices of moments. In principle, one can fully characterize continuous-variable quantum state by means of the obtained conditions taking the atmospheric noise into account. Furthermore, we developed a method for simulating atmospheric losses in laboratorybased experiments, which was implemented by our experimental partners. For a faithful application of such simulation strategies, we introduced a calibration method for the used detection systems. General methods for certifying quantum correlations under imperfect conditions using so-called click-counting detectors were introduced and tested in experiments together with our partners. Eventually, we considered the influence of fluctuating free-space losses on quantum information protocols. In particular, we studied a continuous-variable teleportation protocol for which we showed that certain postselection and adaptive methods lead to an improved performance. The treatment of this teleportation protocol can be seen as an archetype of applications affected by atmospheric losses and the general approach can be adapted to other scenarios. The results of the project provide a deep understanding of atmospheric quantum optics and we are convinced that our results will find their applications in developing and improving quantum communication systems in atmospheric channels.
Projektbezogene Publikationen (Auswahl)
- Entanglement and phase properties of noisy NOON states, Phys. Rev. A 91, 042332 (2015)
M. Bohmann, J. Sperling, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevA.91.042332) - Uncovering Quantum Correlations with Time-Multiplexed Click Detection, Phys. Rev. Lett. 115, 023601 (2015)
J. Sperling, M. Bohmann, W. Vogel, G. Harder, B. Brecht, V. Ansari, and C. Silberhorn
(Siehe online unter https://doi.org/10.1103/PhysRevLett.115.023601) - Gaussian entanglement in the turbulent atmosphere, Phys. Rev. A 94, 010302(R) (2016)
M. Bohmann, A. A. Semenov, J. Sperling, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevA.94.010302) - Direct calibration of click-counting detectors, Phys. Rev. A 95, 033806 (2017)
M. Bohmann, R. Kruse, J. Sperling, C. Silberhorn, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevA.95.033806) - Entanglement verification of noisy NOON states, Phys. Rev. A 96, 012321 (2017)
M. Bohmann, J. Sperling, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevA.96.012321) - Higher-order nonclassical effects in fluctuating-loss channels, Phys. Rev. A 95, 012324 (2017)
M. Bohmann, J. Sperling, A. A. Semenov, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevA.95.012324) - Probing free-space quantum channels with laboratory-based experiments, Phys. Rev. A 95, 063801 (2017)
M. Bohmann, R. Kruse, J. Sperling, C. Silberhorn, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevA.95.063801) - Verifying bound entanglement of dephased Werner states, Phys. Rev. A 96, 042321 (2017)
P. Thomas, M. Bohmann, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevA.96.042321) - Incomplete Detection of Nonclassical Phase-Space Distributions, Phys. Rev. Lett. 120, 063607
M. Bohmann, J. Tiedau, T. Bartey, J. Sperling, C. Silberhorn, and W. Vogel
(Siehe online unter https://doi.org/10.1103/PhysRevLett.120.063607) - Quantumteleportation in atmospheric channels, Phys. Scr. 94 125104 (2019)
K. Hofmann, A. A. Semenov, W. Vogel, and M. Bohmann
(Siehe online unter https://doi.org/10.1088/1402-4896/ab36e0)
