Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Demonstration of an effective ultrastrong coupling between two
  oscillators   When the coupling rate between two quantum systems becomes as large as their
characteristic frequencies, it induces dramatic effects on their dynamics and
even on the nature of their ground state. The case of a qubit coupled to a
harmonic oscillator in this ultrastrong coupling regime has been investigated
theoretically and experimentally. Here, we explore the case of two harmonic
oscillators in the ultrastrong coupling regime. Specifically, we realize an
analog quantum simulation of this coupled system by dual frequency pumping a
nonlinear superconducting circuit. The pump amplitudes directly tune the
effective coupling rate. We observe spectroscopic signature of a mode
hybridization that is characteristic of the ultrastrong coupling. Further we
experimentally demon- strate a key property of the ground state of this
simulated ultrastrong coupling between modes by observing simultaneous
single-mode and two-mode squeezing of the radiated field below vacuum
fluctuations.

27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio