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Simulating Supercool Quantum Bits (Qubits)
Using High Frequency Structure Simulator (HFSS)
This material is based upon work supported by the National Science Foundation
under Grant No. EEC-0540832.
Neno Fuller1, Yanbing Liu2, Andrew Houck2, 1 – Brooklyn College, Brooklyn, NY, 11210, USA
2 – Princeton University, Princeton, NJ, 08544, USA
www.mirthecenter.org
There are many
approaches to QC. We
study cavity quantum
electrodynamics (cQED)
where our qubit is a
superconducting circuit
called the “transmon”.
1. Interaction between the environment and qubit reduces
qubit lifetime
2. Use of filters to remove unwanted electromagnetic modes
3. Utilize purcell effect to increase lifetime (T1) of qubit
Background
Motivation
Simulation
The basic unit of
information in classical
computing is represented
by a “bit”. In quantum
computing (QC) it is a
“qubit”
Schematic representation of the filter: Zlo
and Zhi represent different characteristic
impedances
This is our simulated filter. The alternating
shades of yellow and green on the plane
of the device represent the alternating
impedances.
The tetrahedral sections are part of the
mesh of HFSS. These are the finite
elements used to solve Maxwell's
equations within the device.
Data & Analysis
• Model qubit coupled to
filter
• Calculate T1 from HFSS
admittance data
• Utilize HFSS for circuit
optimization
• Add more steps to
filtration
Future Work
I would personally like to thank Professor Andrew Houck,
Yanbing Liu and the entire Houck lab for their patience
and guidance.
The high frequency structure simulator (HFSS) is a finite element method solver for
electromagnetic structures. We use it to simulate the cavity and filter.
We model the filter using two
approaches: HFSS and Microwave
Office (AWR).
HFSS includes the electromagnetic
environment while modeling the filter;
whereas AWR does not.
On the top left we see HFSS’s
frequency response of the filter. Below
that we have AWR’s.
Qualitatively, the two responses
agree. However, in the HFSS result,
we see a slight bump around 7.60
GHz. This may be indicative of an
environmental effect.
Conclusion
• HFSS models the
components of our
system correctly
• Problems modeling full
system which has more
to do with incorrect
modeling parameters
We would like to thank
MIRTHE and our fellow
MIRTHE scholars for a
enriching and prosperous
summer experience.
Acknowledgments
The purcell filter is
composed of five
coplanar waveguides
of alternating
impedances.
Device image of
superconducting purcell
filter