Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:quant-ph/0603212 · Journal of Physics A Mathematical and General

Quantum baker maps with controlled-not coupling

Raúl O Vallejos, Pedro R del Santoro, Alfredo M Ozorio de Almeida

Published Apr 19, 2006• 4 citations
arXivHTMLPDF

Abstract

The characteristic stretching and squeezing of chaotic motion is linearized within the finite number of phase space domains which subdivide a classical baker map. Tensor products of such maps are also chaotic, but a more interesting generalized baker map arises if the stacking orders for the factor maps are allowed to interact. These maps are readily quantized, in such a way that the stacking interaction is entirely attributed to primary qubits in each map, if each j th subsystem has Hilbert space dimension . We here study the particular example of two baker maps that interact via a controlled-not interaction, which is a universal gate for quantum computation. Numerical evidence indicates that the control subspace becomes an ideal Markovian environment for the target map in the limit of large Hilbert space dimension.

DOI
10.1088/0305-4470/39/18/028

Related papers

Quantum baker maps with controlled-NOT coupling

Vallejos, R O, Santoro, P R, D'Almeida, A M O

The characteristic stretching and squeezing of chaotic motion is linearized within the finite number of phase space domains which subdivide a classical baker map. Tensor products of such maps are also chaotic, but a more interesting generalized baker map arises if the stacking orders for the factor maps are allowed to interact. These maps are readily quantized, in such a way that the stacking interaction is entirely attributed to primary qubits in each map, if each subsystem has power-of-two Hilbert space dimension. We here study the particular example of two baker maps that interact via a controlled-not interaction. Numerical evidence indicates that the control subspace becomes an ideal Markovian environment for the target map in the limit of large Hilbert space dimension.

•Mar 23, 2006•4 citations

Linear optics simulations of the quantum baker’s map

John C. Howell, John A. Yeazell

The unitary evolution of linear optics can be used to model quantum computational networks. In this paper, a quantum simulation of a classically chaotic map (the baker's map) is developed using linear optics. Two different models are presented. The first model employs only 50-50 beam splitters and phase shifters to simulate universal 2-qubit gates of a quantum computer. The second model uses the discrete Fourier transform generated by symmetric $N\ifmmode\times\else\texttimes\fi{}N$ fiber couplers. If single photons are used as inputs for these linear optics models, the result is a physical realization of the quantum baker's map.

Physical Review A•Dec 13, 1999•9 citations

Hypersensitivity and chaos signatures in the quantum baker's maps

A J Scott, Todd A. Brun, Carlton M. Caves +1 more

Classical chaotic systems are distinguished by their sensitive dependence on initial conditions. The absence of this property in quantum systems has lead to a number of proposals for perturbation-based characterizations of quantum chaos, including linear growth of entropy, exponential decay of fidelity, and hypersensitivity to perturbation. All of these accurately predict chaos in the classical limit, but it is not clear that they behave the same far from the classical realm. We investigate the dynamics of a family of quantizations of the baker's map, which range from a highly entangling unitary transformation to an essentially trivial shift map. Linear entropy growth and fidelity decay are exhibited by this entire family of maps, but hypersensitivity distinguishes between the simple dynamics of the trivial shift map and the more complicated dynamics of the other quantizations. This conclusion is supported by an analytical argument for short times and numerical evidence at later times.

arXiv:quant-ph/0606102•Journal of Physics A Mathematical and General•Oct 10, 2006•22 citations

Generalized quantum baker maps as perturbations of a simple kernel

Leonardo Ermann, Marcos Saraceno

We present a broad family of quantum baker maps that generalize the proposal of Schack and Caves to any even Hilbert space with arbitrary boundary conditions. We identify a structure, common to all maps consisting of a simple kernel perturbed by diffraction effects. This "essential" baker's map has a different semiclassical limit and can be diagonalized analytically for Hilbert spaces spanned by qubits. In all cases this kernel provides an accurate approximation to the spectral properties-eigenvalues and eigenfunctions-of all the different quantizations.

arXiv:nlin/0606021•Physical Review E•Oct 5, 2006•12 citations

Modular multiplication operator and quantized baker’s maps

Arul Lakshminarayan

The modular multiplication operator, a central subroutine in Shor's factoring algorithm, is shown to be a coherent superposition of two quantum baker's maps when the multiplier is 2. The classical limit of the maps being completely chaotic, it is shown that there exist perturbations that push the modular multiplication operator into regimes of generic quantum chaos with spectral fluctuations that are those of random matrices. For the initial state of relevance to Shor's algorithm we study fidelity decay due to phase and bit-flip errors in a single qubit and show exponential decay with shoulders at multiples or half-multiples of the order. A simple model is used to gain some understanding of this behavior.

arXiv:0707.2155•Physical Review A•Oct 24, 2007•6 citations

The classical limit of the quantum baker's map

Mark Morgan-Tracy

This work concerns the finding of the semi-classical form of the coherent state representation for the class of quantum baker’s maps defined by Schack and Caves. It begins by introducing the finite-dimensional Hilbert space on which the quantum baker’s map is defined. Its pertinent features including the all important symmetry operators are introduced and given a full explanation. We also introduce the finite-dimensional phase space which will give the semi-classical limit a geometrical interpretation. For a D dimensional Hilbert space, the finite-dimensional phase space is found to be a grid with D2 points. Each point corresponds to a particular pair of position and momentum displacement operator eigenphases. We then detail the derivation of the finite-dimension version of the Wigner function, a quasi-distribution for the finite-dimensional phase space. We show that its most “irregular” feature, mainly its property of having more values than was thought necessary, can be explained by its correct behavior under the symmetry operations, a feature lacking in other Wigner candidates. However, even this special choice for the Wigner function proves unusable in the semi-classical limit as it is found to have a non-convergent limit. We then turn to another possible phase space function: the Q-function. It being necessary to find a suitable coherent state for the finite-dimensional Hilbert space, we begin by studying the properties of the periodically continued Gaussian states. These are the typical Weyl coherent states made periodic in both position and momentum such as to make them legitimate finite-dimensional states. Developing certain mathematical techniques allows us to show that they have compatible position and momentum representations, that a subset of them are complete and can be used to define a Q-function, and that this function obeys all of the symmetry properties. Finally, we use these coherent states to find a representation for the propagator of the quantum baker’s map. In the semi-classical limit, i.e. the large dimension limit, this representation is found, for most of the maps, to take a form of the exponentiation of the classical map’s generating function. This form was predicted long ago by Van Vleck as indicator of an operator’s classical limit. Therefore, we assert that these maps limit to the classically chaotic baker’s map. In certain limiting schemes, however, the Schack-Caves maps do not reach this form and must be given a different interpretation.

•Jan 1, 2002•1 citation
The characteristic stretching and squeezing of chaotic motion is linearized within the finite number of phase space domains which subdivide a classical baker map. Tensor products of such maps are also chaotic, but a more interesting generalized baker map arises if the stacking orders for the factor maps are allowed to interact. These maps are readily quantized, in such a way that the stacking interaction is entirely attributed to primary qubits in each map, if each j th subsystem has Hilbert space dimension . We here study the particular example of two baker maps that interact via a controlled-not interaction, which is a universal gate for quantum computation. Numerical evidence indicates that the control subspace becomes an ideal Markovian environment for the target map in the limit of large Hilbert space dimension.
The characteristic stretching and squeezing of chaotic motion is linearized within the finite number of phase space domains which subdivide a classical baker map. Tensor products of such maps are also chaotic, but a more interesting generalized baker map arises if the stacking orders for the factor maps are allowed to interact. These maps are readily quantized, in such a way that the stacking interaction is entirely attributed to primary qubits in each map, if each subsystem has power-of-two Hilbert space dimension. We here study the particular example of two baker maps that interact via a controlled-not interaction. Numerical evidence indicates that the control subspace becomes an ideal Markovian environment for the target map in the limit of large Hilbert space dimension.
The unitary evolution of linear optics can be used to model quantum computational networks. In this paper, a quantum simulation of a classically chaotic map (the baker's map) is developed using linear optics. Two different models are presented. The first model employs only 50-50 beam splitters and phase shifters to simulate universal 2-qubit gates of a quantum computer. The second model uses the discrete Fourier transform generated by symmetric $N\ifmmode\times\else\texttimes\fi{}N$ fiber couplers. If single photons are used as inputs for these linear optics models, the result is a physical realization of the quantum baker's map.
Classical chaotic systems are distinguished by their sensitive dependence on initial conditions. The absence of this property in quantum systems has lead to a number of proposals for perturbation-based characterizations of quantum chaos, including linear growth of entropy, exponential decay of fidelity, and hypersensitivity to perturbation. All of these accurately predict chaos in the classical limit, but it is not clear that they behave the same far from the classical realm. We investigate the dynamics of a family of quantizations of the baker's map, which range from a highly entangling unitary transformation to an essentially trivial shift map. Linear entropy growth and fidelity decay are exhibited by this entire family of maps, but hypersensitivity distinguishes between the simple dynamics of the trivial shift map and the more complicated dynamics of the other quantizations. This conclusion is supported by an analytical argument for short times and numerical evidence at later times.
We present a broad family of quantum baker maps that generalize the proposal of Schack and Caves to any even Hilbert space with arbitrary boundary conditions. We identify a structure, common to all maps consisting of a simple kernel perturbed by diffraction effects. This "essential" baker's map has a different semiclassical limit and can be diagonalized analytically for Hilbert spaces spanned by qubits. In all cases this kernel provides an accurate approximation to the spectral properties-eigenvalues and eigenfunctions-of all the different quantizations.
The modular multiplication operator, a central subroutine in Shor's factoring algorithm, is shown to be a coherent superposition of two quantum baker's maps when the multiplier is 2. The classical limit of the maps being completely chaotic, it is shown that there exist perturbations that push the modular multiplication operator into regimes of generic quantum chaos with spectral fluctuations that are those of random matrices. For the initial state of relevance to Shor's algorithm we study fidelity decay due to phase and bit-flip errors in a single qubit and show exponential decay with shoulders at multiples or half-multiples of the order. A simple model is used to gain some understanding of this behavior.
This work concerns the finding of the semi-classical form of the coherent state representation for the class of quantum baker’s maps defined by Schack and Caves. It begins by introducing the finite-dimensional Hilbert space on which the quantum baker’s map is defined. Its pertinent features including the all important symmetry operators are introduced and given a full explanation. We also introduce the finite-dimensional phase space which will give the semi-classical limit a geometrical interpretation. For a D dimensional Hilbert space, the finite-dimensional phase space is found to be a grid with D2 points. Each point corresponds to a particular pair of position and momentum displacement operator eigenphases. We then detail the derivation of the finite-dimension version of the Wigner function, a quasi-distribution for the finite-dimensional phase space. We show that its most “irregular” feature, mainly its property of having more values than was thought necessary, can be explained by its correct behavior under the symmetry operations, a feature lacking in other Wigner candidates. However, even this special choice for the Wigner function proves unusable in the semi-classical limit as it is found to have a non-convergent limit. We then turn to another possible phase space function: the Q-function. It being necessary to find a suitable coherent state for the finite-dimensional Hilbert space, we begin by studying the properties of the periodically continued Gaussian states. These are the typical Weyl coherent states made periodic in both position and momentum such as to make them legitimate finite-dimensional states. Developing certain mathematical techniques allows us to show that they have compatible position and momentum representations, that a subset of them are complete and can be used to define a Q-function, and that this function obeys all of the symmetry properties. Finally, we use these coherent states to find a representation for the propagator of the quantum baker’s map. In the semi-classical limit, i.e. the large dimension limit, this representation is found, for most of the maps, to take a form of the exponentiation of the classical map’s generating function. This form was predicted long ago by Van Vleck as indicator of an operator’s classical limit. Therefore, we assert that these maps limit to the classically chaotic baker’s map. In certain limiting schemes, however, the Schack-Caves maps do not reach this form and must be given a different interpretation.