Decoherence-Induced Continuous Pointer States

Decoherence-induced continuous pointer states.

We investigate the reduced dynamics in the Markovian approximation of an infinite quantum spin system linearly coupled to a phonon field at positive temperature. The achieved diagonalization leads to a selection of the continuous family of pointer states corresponding to a configuration space of the one-dimensional Ising model. Such a family provides a mathematical description of an apparatus w...

Decoherence of quantum fields: Pointer states and predictability.

We study environmentally induced decoherence of an electromagnetic eld in a homogeneous, linear, dielectric medium. We derive an independent oscillator model for such an environment, which is su ciently realistic to encompass essentially all of linear physical optics. Applying the \predictability sieve" to the quantum eld, and introducing the concept of a \quantum halo", we recover the familiar...

Decoherence and pointer states in small antiferromagnets: A benchmark test

We study the decoherence process of a four spin-1/2 antiferromagnet that is coupled to an environment of spin-1/2 particles. The preferred basis of the antiferromagnet is discussed in two limiting cases and we identify two exact pointer states. Decoherence near the two limits is examined whereby entropy is used to quantify the robustness of states against environmental coupling. We find that cl...

Highly Nonclassical Quantum States and Environment Induced Decoherence Highly Nonclassical Quantum States and Environment Induced Decoherence

Decoherence, pointer engineering, and quantum state protection.

We present a proposal for protecting states against decoherence, based on the engineering of pointer states. We apply this procedure to the vibrational motion of a trapped ion, and show how to protect qubits, squeezed states, approximate phase eigenstates, and superpositions of coherent states.