42,033 research outputs found
Short Quantum Games
In this thesis we introduce quantum refereed games, which are quantum
interactive proof systems with two competing provers. We focus on a restriction
of this model that we call "short quantum games" and we prove an upper bound
and a lower bound on the expressive power of these games.
For the lower bound, we prove that every language having an ordinary quantum
interactive proof system also has a short quantum game. An important part of
this proof is the establishment of a quantum measurement that reliably
distinguishes between quantum states chosen from disjoint convex sets.
For the upper bound, we show that certain types of quantum refereed games,
including short quantum games, are decidable in deterministic exponential time
by supplying a separation oracle for use with the ellipsoid method for convex
feasibility.Comment: MSc thesis, 79 pages single-space
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/
Quantum Interactive Proofs with Competing Provers
This paper studies quantum refereed games, which are quantum interactive
proof systems with two competing provers: one that tries to convince the
verifier to accept and the other that tries to convince the verifier to reject.
We prove that every language having an ordinary quantum interactive proof
system also has a quantum refereed game in which the verifier exchanges just
one round of messages with each prover. A key part of our proof is the fact
that there exists a single quantum measurement that reliably distinguishes
between mixed states chosen arbitrarily from disjoint convex sets having large
minimal trace distance from one another. We also show how to reduce the
probability of error for some classes of quantum refereed games.Comment: 13 pages, to appear in STACS 200
Quantum coherence, correlated noise and Parrondo games
We discuss the effect of correlated noise on the robustness of quantum
coherent phenomena. First we consider a simple, toy model to illustrate the
effect of such correlations on the decoherence process. Then we show how
decoherence rates can be suppressed using a Parrondo-like effect. Finally, we
report the results of many-body calculations in which an
experimentally-measurable quantum coherence phenomenon is significantly
enhanced by non-Markovian dynamics arising from the noise source.Comment: 8 page
Evolutionary quantum game
We present the first study of a dynamical quantum game. Each agent has a
`memory' of her performance over the previous m timesteps, and her strategy can
evolve in time. The game exhibits distinct regimes of optimality. For small m
the classical game performs better, while for intermediate m the relative
performance depends on whether the source of qubits is `corrupt'. For large m,
the quantum players dramatically outperform the classical players by `freezing'
the game into high-performing attractors in which evolution ceases.Comment: 4 pages in two-column format. 4 figure
Quantum interactive proofs with short messages
This paper considers three variants of quantum interactive proof systems in
which short (meaning logarithmic-length) messages are exchanged between the
prover and verifier. The first variant is one in which the verifier sends a
short message to the prover, and the prover responds with an ordinary, or
polynomial-length, message; the second variant is one in which any number of
messages can be exchanged, but where the combined length of all the messages is
logarithmic; and the third variant is one in which the verifier sends
polynomially many random bits to the prover, who responds with a short quantum
message. We prove that in all of these cases the short messages can be
eliminated without changing the power of the model, so the first variant has
the expressive power of QMA and the second and third variants have the
expressive power of BQP. These facts are proved through the use of quantum
state tomography, along with the finite quantum de Finetti theorem for the
first variant.Comment: 15 pages, published versio
- …