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Abstract |
Given their weak dissipation, large non-linearity and versatility, Josephson junction
metamaterials constitute a promising platform to explore a large class of physical
phenomena, from quantum phase transitions to non-linear quantum optics in the
microwave domain. In this talk I will discuss two recent experiments.
First, I will report on the measurement of a fully-tunable model system where a long
chain of several thousands linear Josephson elements, acting as a strongly dissipative
environment, is terminated by a small Josephson junction endowed with a strong non-
linearity, acting as a single impurity. Using this quantum simulator we could test
predictions of the Boundary Sine Gordon model, including non-perturbative
renormalization of the Josephson energy or many-body dissipation. It is interesting to
note that, in some parameter ranges, the explanation of our data exceeds the capabilities
of the most advanced many-body numerical techniques.
Then, I will discuss our observation of quantized current steps in the current-voltage
characteristic of these Josephson junction metamaterials and their interpretation in the
context of Bloch oscillations and quantum metrology. |
