1993, 26 (7) | Bernard Derrida, M. R. Evans, V. Hakim, V. Pasquier
This paper presents an exact solution of the one-dimensional asymmetric exclusion model using a matrix formulation. The model describes particles hopping in a preferred direction with hard-core interactions, and it is solved exactly for open boundary conditions. The key idea is to represent the weights of each configuration in the steady state as a product of non-commuting matrices. This approach reduces the problem to finding two matrices and two vectors that satisfy simple algebraic rules. The matrices are infinite-dimensional in the general case, but they can be simplified in specific scenarios.
The paper discusses the steady state of the system, showing that the matrix formulation indeed gives the correct weights. It then derives exact expressions for the current and density profiles. The current is calculated, leading to a phase diagram consisting of three phases: low-density, high-density, and maximal current. The density profiles are analyzed both far from the boundaries and near the boundaries, showing that they are constant in the bulk except along the first-order transition line.
The paper also discusses two possible generalizations of the results: the partially asymmetric exclusion process and the case of a mixture of two kinds of particles. For the partially asymmetric exclusion process, the model is extended to allow particles to hop both left and right with different probabilities. The paper shows that the matrix formulation can be adapted to this case. For the case of a mixture of two kinds of particles, the model is extended to include two types of particles, and the matrix formulation is used to derive the steady-state weights.
The paper concludes that the matrix approach provides a powerful and flexible method for solving the asymmetric exclusion model and its generalizations. It allows for the derivation of exact expressions for the current, densities, and correlation functions, and it can be extended to more complex systems. The results are consistent with previous studies and provide new insights into the behavior of the model in different phases.This paper presents an exact solution of the one-dimensional asymmetric exclusion model using a matrix formulation. The model describes particles hopping in a preferred direction with hard-core interactions, and it is solved exactly for open boundary conditions. The key idea is to represent the weights of each configuration in the steady state as a product of non-commuting matrices. This approach reduces the problem to finding two matrices and two vectors that satisfy simple algebraic rules. The matrices are infinite-dimensional in the general case, but they can be simplified in specific scenarios.
The paper discusses the steady state of the system, showing that the matrix formulation indeed gives the correct weights. It then derives exact expressions for the current and density profiles. The current is calculated, leading to a phase diagram consisting of three phases: low-density, high-density, and maximal current. The density profiles are analyzed both far from the boundaries and near the boundaries, showing that they are constant in the bulk except along the first-order transition line.
The paper also discusses two possible generalizations of the results: the partially asymmetric exclusion process and the case of a mixture of two kinds of particles. For the partially asymmetric exclusion process, the model is extended to allow particles to hop both left and right with different probabilities. The paper shows that the matrix formulation can be adapted to this case. For the case of a mixture of two kinds of particles, the model is extended to include two types of particles, and the matrix formulation is used to derive the steady-state weights.
The paper concludes that the matrix approach provides a powerful and flexible method for solving the asymmetric exclusion model and its generalizations. It allows for the derivation of exact expressions for the current, densities, and correlation functions, and it can be extended to more complex systems. The results are consistent with previous studies and provide new insights into the behavior of the model in different phases.