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2016, arXiv: General Physics
Even though it has been almost a century since quantum mechanics planted roots, the field has its share of unresolved problems. It could be the result of a wrong mathematical structure providing inadequate understanding of the quantum phenomena.
New Research in Quantum Physics, 2003
We review aspects of classical and quantum mechanics of many anyons confined in an oscillator potential. The quantum mechanics of many anyons is complicated due to the occurrence of multivalued wavefunctions. Nevertheless there exists, for arbitrary number of anyons, a subset of exact solutions which may be interpreted as the breathing modes or equivalently collective modes of the full system. Choosing the three-anyon system as an example, we also discuss the anatomy of the so called "missing" states which are in fact known numerically and are set apart from the known exact states by their nonlinear dependence on the statistical parameter in the spectrum.
Physics Letters B, 1995
We solve, by separation of variables, the problem of three anyons with a harmonic oscillator potential. The anyonic symmetry conditions from cyclic permutations are separable in our coordinates. The conditions from two-particle transpositions are not separable, but can be expressed as reflection symmetry conditions on the wave function and its normal derivative on the boundary of a circle. Thus the problem becomes one-dimensional. We solve this problem numerically by discretization. N-point discretization with very small N is often a good first approximation, on the other hand convergence as N → ∞ is sometimes very slow.
2011
In nature one observes that in three space dimensions particles are either symmetric under interchange (bosons) or antisymmetric (fermions). These phases give rise to the two possible “statistics” that one observes. In two dimensions, however, a whole continuum of phases is possible.“Anyon” is a term coined in by Frank Wilczek to describe particles in 2 dimensions that can acquire “any” phase when two or more of them are interchanged.
1996
We consider the analog in one spatial dimension of the Bose-Fermi transmutation for planar systems. That is, the construction of a purely bosonic effective local theory starting from a system of bosons and fermions upon integration over the fermionic variables. We consider a quantum mechanical system of a spin 1/2 particle coupled to an abelian gauge field, which is classically invariant under gauge transformations and charge conjugation. It is found that, unless the flux enclosed by the particle orbits is quantized, and the spin takes a value n + 1/2, at least one of the two symmetries would be anomalous. Thus, charge conjugation invariance and the existence of abelian instantons simultaneously avoid the anomaly and force the particles to be
Physics Letters B, 1995
The possibility of excitations with fractional spin and statististics in 1 + 1 dimensions is explored. The configuration space of a two-particle system is the half-line. This makes the Hamiltonian self-adjoint for a family of boundary conditions parametrized by one real number γ. The limit γ → 0, (∞) reproduces the propagator of non-relativistic particles whose wavefunctions are even (odd) under particle exchange. A relativistic ansatz is also proposed which reproduces the correct Polyakov spin factor for the spinning particle in 1 + 1 dimensions. These checks support validity of the interpretation of γ as a parameter related to the "spin" that interpolates continuously between bosons (γ = 0) and fermions (γ = ∞). Our approach can thus be useful for obtaining the propagator for one-dimensional anyons.
Annals of Physics, 2008
The dichotomy between fermions and bosons is at the root of many physical phenomena, from metallic conduction of electricity to super-fluidity, and from the periodic table to coherent propagation of light. The dichotomy originates from the symmetry of the quantum mechanical wave function to the interchange of two identical particles. In systems that are confined to two spatial dimensions particles that are neither fermions nor bosons, coined ''anyons'', may exist. The fractional quantum Hall effect offers an experimental system where this possibility is realized. In this paper we present the concept of anyons, we explain why the observation of the fractional quantum Hall effect almost forces the notion of anyons upon us, and we review several possible ways for a direct observation of the physics of anyons. Furthermore, we devote a large part of the paper to non-abelian anyons, motivating their existence from the point of view of trial wave functions, giving a simple exposition of their relation to conformal field theories, and reviewing several proposals for their direct observation.
Journal of Mathematical Physics, 2006
Relativistic and nonrelativistic anyons are described in a unified formalism by means of the coadjoint orbits of the symmetry groups in the free case as well as when there is an interaction with a constant electromagnetic field. To deal with interactions we introduce the extended Poincaré and Galilei Maxwell groups.
2010
Topological quantum computation may provide a robust approach for encoding and manipulating information utilizing the topological properties of anyonic quasi-particle excitations. We develop an efficient means to map between dense and sparse representations of quantum information (qubits) and a simple construction of multi-qubit gates, for all anyon models from Chern-Simons-Witten SU(2) k theory that support universal quantum computation by braiding (k ≥ 3, k = 4). In the process, we show how the constructions of topological quantum memory and gates for k = 2, 4 connect naturally to those for k ≥ 3, k = 4, unifying these concepts in a simple framework. Furthermore, we illustrate potential extensions of these ideas to other anyon models outside of Chern-Simons-Witten field theory.
Nuclear Physics B, 1993
A U(1) gauge theory of a particle with arbitrary spin in three space-time dimensions is introduced. All the spin-dependent effects are a consequence of a direct coupling of the gauge field to the Chern-Simons field responsible for the shift in spin and statistics. Two approaches in relativistic quantum mechanics which take a spin-0 or a spin-1/2 state as starting point are shown to be equivalent and the result is that the total spin dependence reduces to a magnetic coupling with a gyromagnetic ratio g = 2 for any spin.
Physical Review D Particles and Fields, 1994
The momentum operator representation of nonrelativistic anyons is developed in the Chern-Simons formulation of fractional statistics. The connection between anyons and the q-deformed bosonic algebra is established.
1996
We consider the analog in one spatial dimension of the Bose-Fermi transmutation for planar systems. That is, the construction of a purely bosonic effective local theory starting from a system of bosons and fermions upon integration over the fermionic variables. We consider a quantum mechanical system of a spin 1/2 particle coupled to an abelian gauge field, which is classically invariant under gauge transformations and charge conjugation. It is found that, unless the flux enclosed by the particle orbits is quantized, and the spin takes a value n + 1/2, at least one of the two symmetries would be anomalous. Thus, charge conjugation invariance and the existence of abelian instantons simultaneously avoid the anomaly and force the particles to be
Physics Letters B, 1991
We consider systems containing two or more distinct species of particles in two spatial dimensions. In quantizations of these systems, the statistics of composites containing more than one type of particle are not completely determined by the statistics of the constituents. In particular there exist quantum theories in which two bosons can combine to form an anyon with any desired statistical angle. We demonstrate these results using the topological approach to quantum kinematics, which in this case leads to a generalization of ordinary braid theory in two dimensions. Comparisons are made to three-dimensional systems.
2016
The aim of this text is to provide an introduction to the theory of topological quantum computation. We give an introduction to the theory of anyons (two-dimensional quasi-particle excitations that have exotic statistics) and how we can use these to perform fault-tolerant quantum computation. Additionally, we give a complete description of an exactly solvable spin lattice model whose local low-energy excitations of the Hamiltonian behave as anyons. We conclude by indicating how this model can be generalized so as to perform universal quantum computation.
2012
We study a 2+1 dimensional theory of bosons and fermions with an ω ∝ k 2 dispersion relation. The most general interactions consistent with specific symmetries impart fractional statistics to the fermions. Unlike examples involving Chern-Simons gauge theories, our statistical phases derive from the exchange of gapless propagating bosons with marginal interactions. Even though no gap exists, we show that the anyonic statistics are precisely defined. Symmetries combine with the vacuum structure to guarantee the non-renormalization of our anyonic phases. arXiv:1205.6816v1 [hep-th] 30 May 2012 1 Despite the absence of a gap, the anyonic phase is well-defined, as we show in section 3.1
Topological quantum computation using abelian anyons in Kitaev model is studied. We initially discuss the basics of quantum computation and then present a brief description of topological quantum computation using anyons. The exact solution of the 2D Kitaev model and the emergence of abelian anyons is also described. We also discuss quantum error correction and error tolerant quantum memory using Kitaev’s toric code. Abelian anyonic quantum computation, though not completely fault-tolerant, the universal gates can be realized by including some non topological operations with the topological operations. We verify an already proposed model to realize the universal gates in 2D Kitaev lattice by explicitly investigating the theoretical implementation. We find that the adiabatic transport of anyons for braiding cannot be directly represented by some loop operator if they are to be used for a controlled gate operation.
1994
The minimal (reduced) and extended canonical formulations for (2+1)dimensional fractional spin particles are considered. We i n v estigate the relationship between them, clearing up the meaning of the coordinates for such particles, and analyse the related question of correlation between spin and momentum. The classical lagrangian corresponding to the extended canonical formulation is constructed, and its gauge symmetries are identied. The quantization in both formulations is discussed.
Annals of Physics, 2019
Traditional anyons in two dimensions have generalized exchange statistics governed by the braid group. By analyzing the topology of configuration space, we discover that an alternate generalization of the symmetric group governs particle exchanges when there are hard-core three-body interactions in one-dimension. We call this new exchange symmetry the traid group and demonstrate that it has abelian and non-abelian representations that are neither bosonic nor fermionic, and which also transform differently under particle exchanges than braid group anyons. We show that generalized exchange statistics occur because, like hard-core two-body interactions in two dimensions, hard-core three-body interactions in one dimension create defects with co-dimension two that make configuration space no longer simply-connected. Ultracold atoms in effectively onedimensional optical traps provide a possible implementation for this alternate manifestation of anyonic physics.
Physical Review A, 2012
We describe how continuous-variable abelian anyons, created on the surface of a continuousvariable analogue of Kitaev's lattice model can be utilized for quantum computation. In particular, we derive protocols for the implementation of quantum gates using topological operations. We find that the topological operations alone are insufficient for universal quantum computation which leads us to study additional non-topological operations such as offline squeezing and single-mode measurements. It is shown that these in conjunction with a non-Gaussian element allow for universal quantum computation using continuous-variable abelian anyons.
2020
We study the dynamics of bosonic and fermionic anyons defined on a one-dimensional lattice, under the effect of Hamiltonians quadratic in creation and annihilation operators, commonly referred to as linear optics. These anyonic models are obtained from deformations of the standard bosonic or fermionic commutation relations via the introduction of a non-trivial exchange phase between different lattice sites. We study the effects of the anyonic exchange phase on the usual bosonic and fermionic bunching behaviors. We show how to exploit the inherent Aharonov-Bohm effect exhibited by these particles to build a deterministic, entangling two-qubit gate and prove quantum computational universality in these systems. We define coherent states for bosonic anyons and study their behavior under two-mode linear-optical devices. In particular we prove that, for a particular value of the exchange factor, an anyonic mirror can generate cat states, an important resource in quantum information proces...
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