Spontaneous PT-symmetry breaking in lasing dynamics

PT symmetry and spontaneous symmetry breaking in a microwave billiard.

We demonstrate the presence of parity-time (PT) symmetry for the non-Hermitian two-state Hamiltonian of a dissipative microwave billiard in the vicinity of an exceptional point (EP). The shape of the billiard depends on two parameters. The Hamiltonian is determined from the measured resonance spectrum on a fine grid in the parameter plane. After applying a purely imaginary diagonal shift to the...

Nonlinearly PT -symmetric systems: Spontaneous symmetry breaking and transmission resonances

We consider a class of PT -symmetric systems which include mutually matched nonlinear loss and gain (in other words, a class of PT -invariant Hamiltonians in which both the harmonic and anharmonic parts are non-Hermitian). For a basic system in the form of a dimer, symmetric and asymmetric eigenstates, including multistable ones, are found analytically. We demonstrate that, if coupled to a line...

Dynamics of spontaneous symmetry breaking in the Weinberg-Salam theory

Solving for p,p' gives (2) The need for fundamental scalar fields in the theory of weak and electromagnetic forces' is a serious flaw. Aside from the subjective esthetic argument, there exists a real difficulty connected with the quadratic mass divergences which always accompany scalar fields. ' These divergences violate a concept of naturalness which requires the observable properties of a the...

Nonperturbative Spontaneous Symmetry Breaking

One of the most astonishing results of quantum field theory is spontaneous symmetry breaking. One can say that it is the situation when something arises from the quantization. This means that on the quantum level one has something that was not present on the classical level. Coleman and Weinberg [1] write : “ . . . higher-order effects may qualitatively change the character of a physical theory...

Spontaneous Symmetry Breaking