S-equivalent Lagrangians for free particles and canonical quantization

Ian H. Redmount, Wai-Mo Suen, K. Young

One classical theory, as determined by an equation of motion or set of classical trajectories, can correspond to many unitarily {\em in}equivalent quantum theories upon canonical quantization. This arises from a remarkable ambiguity, not previously investigated, in the construction of the classical (and hence the quantized) Hamiltonian or Lagrangian. This ambiguity is illustrated for systems with one degree of freedom: An arbitrary function of the constants of motion can be introduced into this construction. For example, the nonrelativistic and relativistic free particles follow identical classical trajectories, but the Hamiltonians or Lagrangians, and the canonically quantized versions of these descriptions, are inequivalent. Inequivalent descriptions of other systems, such as the harmonic oscillator, are also readily obtained.

E. I. Bogdanov

Nikolai Andreevich Tyurin

Eqab M. Rabei, Abdul-Wali Ajlouni, H. B. Ghassib

Following our work on the quantization of nonconservative systems using fractional calculus, the canonical quantization of a system of free particles in a dissipative medium is carried out according to the Dirac method. A suitable Schro¨dinger equation is set up and solved for the Lagrangian representing this system. The wave function is plotted and the damping effect manifests itself very clearly. This formalism is then applied to the problem of energy loss of charged particles when passing through matter. The results are plotted and the relation between the energy loss and the range agrees qualitatively with experimental results.

W. K. Burton

N. Emir Anuar

We present a formalism for which a dissipative system is given by a variational principle. The formalism applies to dynamical systems where its trajectory is monotonic. Subsequently, we derive its Lagrangian and Hamiltonian. From the Hamiltonian, we quantize canonically the classical particle in a viscous media. We study the free quantum particle in a viscous media and the dissipative quantum tunnelling. It is found that the dissipation influences tunnelling probability by a factor that closely resembles the result of Caldeira and Leggett.