Three-level {\Lambda}-type atomic systems with a Pseudo-Hermitian   PT-symmetric Hamiltonian
  We have studied a three-level {\Lambda}-type atomic system with all the energy levels exhibiting decay. The system is described by a pseudo-Hermitian Hamiltonian and subject to certain conditions, the Hamiltonian shows parity-time (PT) symmetry. The probability amplitudes of various atomic levels both below and above the PT-theshold is worked out. 
Amarendra K. Sarma and Balla Prannay
quant-ph physics.optics