Method of Collective Degrees of Freedom in Spin Coherent State Path Integral

نویسندگان

  • Junya Shibata
  • Shin Takagi
چکیده

We present a detailed field theoretic description of those collective degrees of freedom (CDF) which are relevant to study macroscopic quantum dynamics of a quasi-one-dimensional ferromagnetic domain wall. We apply spin coherent state path integral (SCSPI) in the proper discrete time formalism (a) to extract the relevant CDF’s, namely, the center position and the chirality of the domain wall, which originate from the translation and the rotation invariances of the system in question, and (b) to derive effective action for the CDF’s by elimination of environmental zero-modes with the help of the Faddeev-Popov technique. The resulting effective action turns out to be such that both the center position and the chirality can be formally described by boson coherent state path integral. However, this is only formal; there is a subtle departure from the latter.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

روش انتگرال مسیر برای مدل ‌هابارد تک نواره

  We review various ways to express the partition function of the single-band Hubard model as a path integral. The emphasis is made on the derivation of the action in the integrand of the path integral and the results obtained from this approach are discussed only briefly.   Since the single-band Hubbard model is a pure fermionic model on the lattice and its Hamiltonian is a polynomial in creat...

متن کامل

Macroscopic Quantum Dynamics of a Free Domain Wall in a Ferromagnet

We study macroscopic quantum dynamics of a free domain wall in a quasione-dimensional ferromagnet by use of the spin-coherent-state path integral in discrete-time formalism. Transition amplitudes between typical states are quantitatively discussed by use of stationary-action approximation with respect to collective degrees of freedom representing the center position and the chirality of the dom...

متن کامل

M ay 2 00 3 Semiclassical theory of spin - orbit interaction in the extended phase space Mikhail

We consider the semiclassical theory in a joint phase space of spin and orbital degrees of freedom. The method is developed from the path integral using the spincoherent-state representation, and yields the trace formula for the density of states. We discuss the limits of weak and strong spin-orbit coupling and relate the present theory to the earlier approaches.

متن کامل

Path integral approach to no-Coriolis approximation in heavy-ion collisions.

We use the two time influence functional method of the path integral approach in order to reduce the dimension of the coupled-channels equations for heavy-ion reactions based on the no-Coriolis approximation. Our method is superior to other methods in that it easily enables us to study the cases where the initial spin of the colliding particle is not zero. It can also be easily applied to the c...

متن کامل

Coherent-state quantization of constrained fermion systems

The quantization of systems with firstand second-class constraints within the coherentstate path-integral approach is extended to quantum systems with fermionic degrees of freedom. As in the bosonic case the importance of path-integral measures for Lagrange multipliers, which in this case are in general expected to be elements of a Grassmann algebra, is explicated. Several examples with firstan...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2001