476 research outputs found
Coalitions in the quantum Minority game: classical cheats and quantum bullies
In a one-off Minority game, when a group of players agree to collaborate they
gain an advantage over the remaining players. We consider the advantage
obtained in a quantum Minority game by a coalition sharing an initially
entangled state versus that obtained by a coalition that uses classical
communication to arrive at an optimal group strategy. In a model of the quantum
Minority game where the final measurement basis is randomized, quantum
coalitions outperform classical ones when carried out by up to four players,
but an unrestricted amount of classical communication is better for larger
coalition sizes.Comment: 12 pages, 1 figur
An introduction to quantum game theory
The application of the methods of quantum mechanics to game theory provides
us with the ability to achieve results not otherwise possible. Both linear
superpositions of actions and entanglement between the players' moves can be
exploited. We provide an introduction to quantum game theory and review the
current status of the subject.Comment: 8 pages, RevTeX; v2 minor changes to the text in light of referees
comments, references added/update
Signal acquisition via polarization modulation in single photon sources
A simple model system is introduced for demonstrating how a single photon
source might be used to transduce classical analog information. The theoretical
scheme results in measurements of analog source samples that are (i) quantized
in the sense of analog-to-digital conversion and (ii) corrupted by random noise
that is solely due to the quantum uncertainty in detecting the polarization
state of each photon. This noise is unavoidable if more than one bit per sample
is to be transmitted, and we show how it may be exploited in a manner inspired
by suprathreshold stochastic resonance. The system is analyzed information
theoretically, as it can be modeled as a noisy optical communication channel,
although unlike classical Poisson channels, the detector's photon statistics
are binomial. Previous results on binomial channels are adapted to demonstrate
numerically that the classical information capacity, and thus the accuracy of
the transduction, increases logarithmically with the square root of the number
of photons, N. Although the capacity is shown to be reduced when an additional
detector nonideality is present, the logarithmic increase with N remains.Comment: 7 pages, 2 figures, accepted by Physical Review E. This version adds
a referenc
The extent and manner of entry of albumin and ferritin into the interior of twitch and slow muscle fibres of the frog and toad
Imperial Users onl
Advantage of a quantum player over a classical one in 2x2 quantum games
We study a general symmetric, entangled, quantum game. When one
player has access only to classical strategies while the other can use the full
range of quantum strategies, there are ``miracle'' moves available to the
quantum player that can direct the result of the game towards the quantum
player's preferred result regardless of the classical player's strategy. The
advantage pertaining to the quantum player is dependent on the degree of
entanglement. Below a critical level, dependent on the payoffs in the game, the
miracle move is of no advantage.Comment: Revtex, 10 pages, 2 tables, 4 figures; v2 typo corrected in table 2,
cosmetic changes to tables and figures, comment added to section VI E; v3
title changed to published title; minor mathematical errors in published
version correcte
Nash equilibria in quantum games with generalized two-parameter strategies
In the Eisert protocol for 2 X 2 quantum games [Phys. Rev. Lett. 83, 3077], a
number of authors have investigated the features arising from making the
strategic space a two-parameter subset of single qubit unitary operators. We
argue that the new Nash equilibria and the classical-quantum transitions that
occur are simply an artifact of the particular strategy space chosen. By
choosing a different, but equally plausible, two-parameter strategic space we
show that different Nash equilibria with different classical-quantum
transitions can arise. We generalize the two-parameter strategies and also
consider these strategies in a multiplayer setting.Comment: 19 pages, 2 eps figure
An optical model for an analogy of Parrondo game and designing Brownian ratchets
An optical model of classical photons propagating through array of many beam
splitters is developed to give a physical analogy of Parrondo's game and
Parrondo-Harmer-Abbott game. We showed both the two games are reasonable game
without so-called game paradox and they are essentially the same. We designed
the games with long-term memory on loop lattice and history-entangled game. The
strong correlation between nearest two rounds of game can make the combination
of two losing game win, lose or oscillate between win and loss. The periodic
potential in Brownian ratchet is analogous to a long chain of beam splitters.
The coupling between two neighboring potential wells is equivalent to two
coupled beam splitters. This correspondence may help us to understand the
anomalous motion of exceptional Brownian particles moving in the opposite
direction to the majority. We designed the capital wave for a game by
introducing correlations into independent capitals instead of sub-games.
Playing entangled quantum states in many coupled classical games obey the same
rules for manipulating quantum states in many body physics.Comment: 18 pages in two colum
Quantum Parrondo's Games
Parrondo's Paradox arises when two losing games are combined to produce a
winning one. A history dependent quantum Parrondo game is studied where the
rotation operators that represent the toss of a classical biased coin are
replaced by general SU(2) operators to transform the game into the quantum
domain. In the initial state, a superposition of qubits can be used to couple
the games and produce interference leading to quite different payoffs to those
in the classical case.Comment: LateX, 10 pages, 2 figures, submitted to Physica A special issue
(Gene Stanley Conference, Sicily, 2001), v2 minor correction to equations, v3
corrections to results section and table, acknowledgement adde
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