Manzoor Ikram

Control of the Goos-Hänchen shift of a light beam via a coherent driving field

We present a proposal to manipulate the Goos-Haenchen shift of a light beam via a coherent control field, which is injected into a cavity configuration containing the two-level atomic medium. It is found that the lateral shifts of the reflected and transmitted probe beams can be easily controlled by adjusting the intensity and detuning of the control field. Using this scheme, the lateral shift at the fixed incident angle can be enhanced (positive or negative) under the suitable conditions on the control field, without changing the structure of the cavity.

Engineering entanglement between two cavity modes

We present a scheme for the generation of entanglement between different modes of radiation field inside high-

Engineering maximally entangled N-photon NOON field states using an atom interferometer based on Bragg regime cavity QED

Q

Entanglement of Gaussian states using a beam splitter

superconducting cavities. Our scheme is based on the interaction of a three-level atom with the cavity field for precalculated interaction times with each mode. This work enables us to generate a complete set of Bell basis states and a quantum entangled Greenberger-Horn-Zeilinger state.

Generation of entangled state between two cavities for fixed number of photons

We propose a scheme for generation of highly non-classical entangled field states of the type in the cavity QED scenario. The scheme utilizes an atomic analogue of the Mach–Zehnder interferometer having a quantized field in the high-Q cavity containing a superposition of zero and one photon that acts as the first beam splitter. The probability for production of the desired states may approach a value close to unity with high fidelity under prevailing experimental conditions.

Entanglement dynamics of a pure bipartite system in dissipative environments

We study an experimental scheme to generate Gaussian two-mode entangled states via beam splitter. Specifically, we consider a nonclassical Gaussian state (squeezed state) and a thermal state as two input modes, and evaluate the degree of entanglement at the output. Experimental conditions to generate entangled outputs are completely identified and the critical thermal noise to destroy entanglement is analytically obtained. By doing so, we discuss the possibility to link the resistance to noise in entanglement generation with the degree of single-mode nonclassicality.

Entanglement dynamics of high-dimensional bipartite field states inside the cavities in dissipative environments

Quantum entanglement plays a key role in many of the applications in the quantum information processing system. In this paper, we present a method for preparing an entangled field state for a fixed number of photons in the two cavities.

Generating entangled states of continuous variables via cross-Kerr nonlinearity

We investigate the phenomenon of sudden death of entanglement in a bipartite system subjected to dissipative environments with arbitrary initial pure entangled state between two atoms. We find that in a vacuum reservoir the presence of the state where both atoms are in excited states is a necessary condition for the sudden death of entanglement. Otherwise entanglement remains for an infinite time and decays asymptotically with the decay of individual qubits. For pure 2-qubit entangled states in a thermal environment, we observe that the sudden death of entanglement always happens. The sudden death time of the entangled states is related to the temperature of the reservoir and the initial preparation of the entangled states.

Atomic state teleportation: from internal to external degrees of freedom

We investigate the phenomenon of sudden death of entanglement in a high-dimensional bipartite system subjected to dissipative environments with an arbitrary initial pure entangled state between two fields in the cavities. We find that in a vacuum reservoir, the presence of the state where one or more than one (two) photons in each cavity are present is a necessary condition for the sudden death of entanglement. Otherwise entanglement remains for infinite time and decays asymptotically with the decay of individual qubits. For pure two-qubit entangled states in a thermal environment, we observe that sudden death of entanglement always occurs. The sudden death time of the entangled states is related to the number of photons in the cavities, the temperature of the reservoir and the initial preparation of the entangled states.

Sub-wavelength atom localization via Autler–Townes spectroscopy: effect of the quantized field

We propose a scheme for generating entanglement of quantum states with continuous variables (coherent states and squeezed vacuum states) of electromagnetical fields. The scheme involves cross-Kerr nonlinearity. It was shown that the cross-Kerr nonlinearity required for generating the superposition and entanglement of squeezed vacuum states is smaller than that required for coherent states. It was also found that the fidelity monotonously decreases with both the increase of the amplitude of the input coherent field and the increase of the deviation of the nonlinear phase shift from π.