Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 34: TR: Quantum Coherence and Quantum Information Systems 2 (jointly with MA and HL)
TT 34.2: Vortrag
Mittwoch, 16. März 2011, 14:15–14:30, HSZ 03
A flux-driven Josephson parametric amplifier for experiments with propagating quantum microwaves — •Edwin P. Menzel1, Alexander Baust1, Frank Deppe1, Peter Eder1, Thomas Niemczyk1, Elisabeth Hoffmann1, Max Haeberlein1, Achim Marx1, Rudolf Gross1, Enrique Solano2, Kunihiro Inomata3, Tsuyoshi Yamamoto3,4, and Yasunobu Nakamura3,4 — 1Walther-Meissner-Institut and TU München, Garching, Germany — 2Universidad del Pais Vasco and Ikerbasque Foundation, Bilbao, Spain — 3RIKEN, Wako-shi, Japan — 4NEC Corporation, Tsukuba, Japan
For the detection of propagating quantum microwaves in circuit QED linear amplifiers are key ingredients. Phase sensitive amplifiers [e.g., Josephson parametric amplifiers (JPA)] in principle allow for the amplification of one signal quadrature without adding noise. In practice, however, internal losses often introduce a finite amount of noise. We have recently shown that, despite such a residual noise, signals on the quantum level can be fully characterized using two amplification chains and suitable correlations [E.P. Menzel et al., PRL 105, 100401 (2010)]. In this work, we characterize a flux-driven JPA. At 5.64 GHz the maximum degenerate gain is 25.5 dB and the signal bandwidth is 1.8 MHz. Phase-insensitive measurements yield a noise temperature of 100±20 mK, which is below the standard quantum limit of 135 mK.
This work is supported by SFB 631, NIM, Basque Government IT4720-10, Spanish MICINN FIS2009-12773-C02-01, and EU project SOLID.