08.05.2014
MPL Distinguished Lecturer Series: Prof Andreas Wallraff
Title: Quantum microwave photonics
Speaker: Prof Andreas Wallraff ETH Zürich, Schweiz
Abstract: Using modern micro and nanofabrication techniques combined with superconducting materials we realize quantum electronic circuits in which we create, store, and manipulate individual microwave photons. The strong interaction of photons with superconducting quantum twolevel systems allows us to probe fundamental quantum effects of microwave radiation and also to develop components for applications in quantum technology. Previously we have realized ondemand single photon sources which we have characterized using correlation function measurements [1] and full quantum state tomography [2]. For this purpose we have developed efficient methods to separate the quantum signals of interest from the noise added by the linear amplifiers used for quadrature amplitude detection [3]. We now regularly employ superconducting parametric amplifiers [4] to perform nearly quantum limited detection of propagating electromagnetic fields. These enable us to probe the entanglement which we generate on demand between stationary qubits and microwave photons freely propagating down a transmission line [5]. Using two independent microwave single photon sources, we have recently performed HongOuMandel experiments at microwave frequencies [6] and have probed the coherence of twomode multiphoton states at the output of a beamsplitter. The nonlocal nature of such states may prove to be useful for distributing entanglement in future smallscale quantum networks.
[1] D. Bozyigit et al., Nat. Phys. 7, 154 (2011) [2] C. Eichler et al., Phys. Rev. Lett. 106, 220503 (2011) [3] C. Eichler et al., Phys. Rev. A 86, 032106 (2012) [4] C. Eichler et al., Phys. Rev. Lett. 107, 113601 (2011) [5] C. Eichler et al., Phys. Rev. Lett. 109, 240501 (2012) [6] C. Lang et al., Nat. Phys. 9, 345348 (2013)
Time, place: Thursday, 8. May 2014, 15:00
Seminarroom, Bau 24, GuentherScharowskyStr. 1
