3,207 research outputs found
Getting the public involved in Quantum Error Correction
The Decodoku project seeks to let users get hands-on with cutting-edge
quantum research through a set of simple puzzle games. The design of these
games is explicitly based on the problem of decoding qudit variants of surface
codes. This problem is presented such that it can be tackled by players with no
prior knowledge of quantum information theory, or any other high-level physics
or mathematics. Methods devised by the players to solve the puzzles can then
directly be incorporated into decoding algorithms for quantum computation. In
this paper we give a brief overview of the novel decoding methods devised by
players, and provide short postmortem for Decodoku v1.0-v4.1.Comment: Extended version of article in the proceedings of the GSGS'17
conference (see https://gsgs.ch/gsgs17/
A simple decoder for topological codes
Here we study an efficient algorithm for decoding the topological codes. It
is based on a simple principle, which should allow straightforward
generalization to complex decoding problems. It is benchmarked with the planar
code for both i.i.d. and spatially correlated errors and is found to compare
well with existing methods.Comment: v3: Corrected error and added data for correlated errors. v4: Added
data for improved version of decoder. This is the published versio
A quantum procedure for map generation
Quantum computation is an emerging technology that promises a wide range of
possible use cases. This promise is primarily based on algorithms that are
unlikely to be viable over the coming decade. For near-term applications,
quantum software needs to be carefully tailored to the hardware available. In
this paper, we begin to explore whether near-term quantum computers could
provide tools that are useful in the creation and implementation of computer
games. The procedural generation of geopolitical maps and their associated
history is considered as a motivating example. This is performed by encoding a
rudimentary decision making process for the nations within a quantum procedure
that is well-suited to near-term devices. Given the novelty of quantum
computing within the field of procedural generation, we also provide an
introduction to the basic concepts involved.Comment: To be published in the proceedings of the IEEE Conference on Game
A repetition code of 15 qubits
The repetition code is an important primitive for the techniques of quantum
error correction. Here we implement repetition codes of at most qubits on
the qubit \emph{ibmqx3} device. Each experiment is run for a single round
of syndrome measurements, achieved using the standard quantum technique of
using ancilla qubits and controlled operations. The size of the final syndrome
is small enough to allow for lookup table decoding using experimentally
obtained data. The results show strong evidence that the logical error rate
decays exponentially with code distance, as is expected and required for the
development of fault-tolerant quantum computers. The results also give insight
into the nature of noise in the device.Comment: 7 page
Parafermions in a Kagome lattice of qubits for topological quantum computation
Engineering complex non-Abelian anyon models with simple physical systems is
crucial for topological quantum computation. Unfortunately, the simplest
systems are typically restricted to Majorana zero modes (Ising anyons). Here we
go beyond this barrier, showing that the parafermion model of
non-Abelian anyons can be realized on a qubit lattice. Our system additionally
contains the Abelian anyons as low-energetic excitations. We
show that braiding of these parafermions with each other and with the
anyons allows the entire Clifford group to be
generated. The error correction problem for our model is also studied in
detail, guaranteeing fault-tolerance of the topological operations. Crucially,
since the non-Abelian anyons are engineered through defect lines rather than as
excitations, non-Abelian error correction is not required. Instead the error
correction problem is performed on the underlying Abelian model, allowing high
noise thresholds to be realized.Comment: 11+10 pages, 14 figures; v2: accepted for publication in Phys. Rev.
X; 4 new figures, performance of phase-gate explained in more detai
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