Dear Tejinder,
Thanks for your reply and your interesting essay. Here are the answers to your two questions:
Q1. While you discuss decoherence, would you also not need to invoke the many worlds interpretation?
A1. No! In Measurement Color Quantum Electrodynamics (MC-QED) (arXiv:0902.4667) it is shown that an intrinsic time irreversibility occurs thru spontaneous symmetry breaking of the CPT symmetry. This generates a time reversal violating quantum measurement interaction in the Hamiltonian of the formalism. If this Hamiltonian is then decomposed into a system part and an environment part this CPT violations causes intrinsically time reversal violating decoherence effects to occur in the reduced density matrix associated with the system part which is traced over the environment part of the Hamilton. These intrinsically time reversal violating decoherence effects do more than just diagonalize the density matrix of the system. Instead they actually project out individual states similar to what you would expect for a Von Neumann projection operator. For this reason MC-QED does not require many worlds interpretation. Instead it dynamically supplies its own interpretation in the context of its formal structure.
Q2. Secondly, can you please explain to me again how the photons carry an arrow of time?
A2: MC-QED is a non-local quantum field theory in which the quantum electrodynamic arrow of time emerges dynamically because the microscopic observer-participant operator structure of the formalism implies that the local time-symmetric "free photon operator" is non-physical since it cannot be given a Measurement Color description. Instead it must be replaced by a Measurement Color Symmetric Total Coupled Radiation Charge-Field photon operator which is non-local and carries a negative time parity under the Wigner Time Reversal operator Tw. Because of this difference between the QED and MC-QED photon operator structure, the physical requirement that a stable vacuum state exists dynamically constrains the MC-QED Heisenberg operator equations of motion to contain a causal retarded quantum electrodynamic arrow of time independent of external thermodynamic or cosmological assumptions.
The MC-QED formalism is a non-local quantum field theory which obeys a generalized time reversal invariance symmetry, where the time reversal operator T is generalized to become the direct product of the Wigner Time Reversal operator Tw and the Radiation Energy-Momentum Flow Reversal operator Tp given by T = Tw x Tp. In this context this implies that the CPT symmetry is conserved in MC-QED where T is generalized to become T= Tw x Tp. However, even though it preserves the generalized T = Tw x Tp symmetry, the presence of the negative Tw parity photon charge-field operator in MC-QED causes it to separately violate both the Tw and the Tp symmetries.
In this context the presence of the negative Wigner Time Reversal parity photon charge-field operator the MC-QED formalism, in conjunction with the physical requirement of a stable vacuum state in MC-QED, spontaneously breaks both the T and the CPT symmetry of the MC-QED formalism by dynamically selecting the operator solution containing a causal, retarded, quantum electrodynamic arrow of time. In this manner the existence of the microscopic arrow of time in MC-QED represents a fundamentally quantum electrodynamic explanation, for irreversible phenomena associated with the Second Law of Thermodynamics, which complements the one supplied by the well-known statistical arguments in phase space.
I hope that this answers your questions. Further comments are appreciated
Best wishes
Darryl