DOI: 10.5061/dryad.zpc866t6v
title: A phononic crystal coupled to a transmission line via an artificial atom. Experimental data for the article figures

description: We study a phononic crystal interacting with an articial atom - a
 superconducting quantum system - in the quantum regime. The phononic
 crystal is made of a long lattice of narrow metallic stripes on a quatz
 surface. The articial atom in turn interacts with a transmission line.
 Therefore, two degrees of freedom of different nature, acoustic and
 electromagnetic, are coupled with a single quantum object. A scattering
 spectrum of propagating electromagnetic waves on the articial atom
 visualizes acoustic modes of the phononic crystal. We simulate the system
 and found quasinormal modes of our phononic crystal and their properties.
 The calculations are consistent with the experimentally found modes, which
 are tted to the dispersion branches of the phononic crystal near the rst
 Brillouin zone edge. Our geometry allows to realize effects of quantum
 acoustics on a simple and compact phononic crystal.
description: Here we present an experimental data used for ploting the
 figures: 2a, 2b, 2c, 3 and for Fig4c inset.  All
 datasets are titled according to the corresponding figure number in the
 manuscript: data_for_Fig_2a.csv
 data_for_Fig_2b.pkl
 data_for_Fig_2c.csv
 data_for_Fig_3.csv
 data_for_Fig4c_inset.csv Our experiment is
 performed at a base temperature T = 15 mK of a dilution refrigerator, so
 that the thermal uctuations are well below the energy of surface acoustic
 phonons, which are in the gigahertz range of frequencies. We implement the
 measurement setup typically used for quantum optics experiments with
 superconducting arti cial atoms. The electromagnetic waves are transmitted
 from a vector network analyzer (VNA) through coaxial cables and a set of
 attenuators at different cooling stages, for suppressing room temperature
 blackbody radiation. Atom-wave interaction results in the scattering of
 the propagated through a transmission line waves, detected as a change in
 phase and amplitude of the transmitted signal close to the qubit resonance
 frequency. The transmitted signal is then amplied by cryogenic and
 room-temperature ampliers and measured by the VNA. The data for the
 Figures 2a, 2b, 2c and 3 by using the method described above.  The
 corresponding data files
 are: data_for_Fig_2a.csv, data_for_Fig_2b.pkl, data_for_Fig_2c.csv, data_for_Fig_3.csv. In measurements for Figures 2b, 2c and 3, we changed the magnetic field by applying current to the coil. Therefore, there is a current column in the data. Figure 2a is a measurement of signal transmission versus frequency for a fixed magnetic field. Accordingly, there is no current column in this data(data_for_Fig_3.csv).  In order to get the data for Fig.4c inset we measured the reflection coefficient of the microwave signal applied directly to the interdigital transducer, which has the same geometry as the phononic crystal. The resonance dips found in this experimental plot correspond to the excitation of quasi-normal modes  
description: All data can be easily visualized. For example, by using the
 library matplotlib in python. Other standard software tools for data
 visualization can also be used as the data in the files is presented as
 columns with obvious headers. Particulary, the table of each dataset can
 be opened in Microsoft Excel.