Hybrid quantum bit based on topological insulators

Date:
April 14, 2022
Source:
Forschungszentrum Juelich
Summary:
With their superior properties, topological qubits could help
achieve a breakthrough in the development of a quantum computer
designed for universal applications. So far, no one has yet
succeeded in unambiguously demonstrating a quantum bit, or qubit
for short, of this kind in a lab.

Scientists have now succeeded in integrating a topological insulator
into a conventional superconducting qubit.



FULL STORY ==========================================================================
With their superior properties, topological qubits could help achieve
a breakthrough in the development of a quantum computer designed for
universal applications. So far, no one has yet succeeded in unambiguously demonstrating a quantum bit, or qubit for short, of this kind in a
lab. However, scientists from Forschungszentrum Ju"lich have now gone
some way to making this a reality.

For the first time, they succeeded in integrating a topological insulator
into a conventional superconducting qubit. Just in time for "World Quantum
Day" on 14 April, their novel hybrid qubit made it to the cover of the
latest issue of the journal Nano Letters.


========================================================================== Quantum computers are regarded as the computers of the future. Using
quantum effects, they promise to deliver solutions for highly complex
problems that cannot be processed by conventional computers in a realistic
time frame.

However, the widespread use of such computers is still a long way
off. Current quantum computers generally contain only a small number of
qubits. The main problem is that they are highly prone to error. The
bigger the system, the more difficult it is to fully isolate it from
its environment.

Many hopes are therefore pinned on a new type of quantum bit -- the
topological qubit. This approach is being pursued by several research
groups as well as companies such as Microsoft. This type of qubit
exhibits the special feature that it is topologically protected; the
particular geometric structure of the superconductors as well as their
special electronic material properties ensure that quantum information is retained. Topological qubits are therefore considered to be particularly
robust and largely immune to external sources of decoherence. They also
appear to enable fast switching times comparable to those achieved by
the conventional superconducting qubits used by Google and IBM in current quantum processors.

However, it is not yet clear whether we will ever succeed in actually
producing topological qubits. This is because a suitable material basis
is still lacking to experimentally generate the special quasiparticles
required for this without any doubt. These quasiparticles are also
known as Majorana states. Until now, they could only be unambiguously demonstrated in theory, but not in experiments. Hybrid qubits, as they
have now been constructed for the first time by the research group led
by Dr. Peter Schu"ffelgen at the Peter Gru"nberg Institute (PGI-9)
of Forschungszentrum Ju"lich, are now opening up new possibilities
in this area. They already contain topological materials at crucial
points. Therefore, this novel type of hybrid qubit provides researchers
with a new experimental platform to test the behaviour of topological
materials in highly sensitive quantum circuits.


========================================================================== Story Source: Materials provided by Forschungszentrum_Juelich. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Tobias W. Schmitt, Malcolm R. Connolly, Michael Schleenvoigt,
Chenlu Liu,
Oscar Kennedy, Jose' M. Cha'vez-Garcia, Abdur R. Jalil, Benjamin
Bennemann, Stefan Trellenkamp, Florian Lentz, Elmar Neumann,
Tobias Lindstro"m, Sebastian E. de Graaf, Erwin Berenschot, Niels
Tas, Gregor Mussler, Karl D. Petersson, Detlev Gru"tzmacher,
Peter Schu"ffelgen.

Integration of Topological Insulator Josephson Junctions in
Superconducting Qubit Circuits. Nano Letters, 2022; 22 (7): 2595
DOI: 10.1021/acs.nanolett.1c04055 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220414110823.htm

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