235 views

442 views

### Is Hamilton's principle compatible with the relativity principle?

The principle of Hamilton in classical mechanics is a fundamental one. It states that the real trajectory of a particle extremize the action $$\int_{t_1}^{t_2} d \tau L (q , \dot{q}, \tau ) .$$ ...
856 views

### What is the relationship between BRST symmetry and gauge symmetry?

As far as i know the BRST symmetry is an infinitesimal (and expanded) version of gauge symmetry. Recently I read the following: "when QFT was reformulated in fiber bundle language for application to ...
777 views

### Why don't people use Hamilton's equations for a relativistic free charged particle?

A charged relativistic free particle has the Hamiltonian in general: $$\mathcal{H} = \sqrt{{\bf p}^2c^2+m^2c^4}.$$ I read somewhere that says, it is possible to go further and say that the EoM are ...
783 views

### What is the relation between the Hamiltonian and Lagrangian in GR to Newtonian mechanics?

The Lagrangian and Hamiltonian in Classical mechanics are given by $\mathcal{L} = T - V$ and $\mathcal{H}=T+V$ respectively. Usual notation for kinetic and potential energy is used. But, in GR they ...
936 views

99 views

198 views

### Are these two square root & non-square root worldline actions equivalent at quantum level? (Kleinert's method)

The relativistic particle action is (in its more natural form) $$A=McS=Mc\int_{\lambda_a}^{\lambda_b}d\lambda\sqrt{x'^2(\lambda)}.\tag{19.12}$$ That action doesn't lend itself easily to a ...