18 research outputs found
Light as quantum back-action nullifying meter
We propose a new method to overcome quantum back-action in a measurement
process using oscillators. An optical oscillator is used as a meter to measure
the parameters of another open oscillator. The optical oscillator is
synthesized such that the optical restoring force counters any perturbations
induced by the quantum back-action phenomena. As a result, it is shown that the
quantum back-action in continuous measurement is suppressed in the low
frequency regime i.e., for frequencies much smaller than the resonance
frequency of the open oscillator. As the meter plays the role of measuring
parameters as well as suppressing the quantum back-action, we call it as
quantum back-action nullifying meter. As an application of this method,
synthesis of quantum back-action nullifying optical oscillator for suppressing
radiation pressure force noise in linear and non-linear optomechanics is
described.Comment: 6 pages, 1 figur
Continuous variable entanglement between propagating optical modes using optomechanics
This article proposes a new method to entangle two spatially separated output
laser fields from an optomechanical cavity with a membrane in the middle. The
radiation pressure force coupling is used to modify the correlations between
the input and the output field quadratures. Then the laser fields at the
optomechanical cavity output are entangled using the quantum back-action
nullifying meter technique. The effect of thermal noise on the entanglement is
studied. For experimentally feasible parameters, the entanglement between the
laser fields survives upto room temperature.Comment: 14 pages, 4 figures, 68 reference
Optical ranging with quantum advantage
The quantum illumination technique requires joint measurement between the
idler and the probe reflected from the low-reflective target present in a noisy
environment. The joint measurement is only possible with prior knowledge about
the target's location. The technique in this article overcomes this limitation
by using entanglement and a cross-correlated homodyne measurement. This
technique does not require quantum storage of the idler and prior knowledge
about the target's distance. The cross-correlation measurement makes this
technique completely immune to environmental noise, as the correlation between
the idler and the environment is zero. The low reflectivity of the target is
negated by increasing the intensity of the reference fields (non-entangled) in
the homodyne. Based on heuristic arguments, a lower bound of the target's
reflectivity for optimum application of this technique is described.Comment: 10 pages, 1 figure, 49 reference
Coherent population transfer with polariton states in circuit QED
This article proposes a new method to increase the efficiency of stimulated
Raman adiabatic passage (STIRAP) in superconducting circuits using a shortcut
to the adiabaticity (STA) method. The STA speeds up the adiabatic process
before decoherence has a significant effect, thus leading to increased
efficiency. This method achieves fast, high-fidelity coherent population
transfer, known as super-adiabatic STIRAP (saSTIRAP), in a dressed
state-engineered system with polariton states in circuit QED
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Controllable enhanced dragging of light in ultradispersive media
Article discussing research on the controllable enhanced dragging of light in ultradispersive media
Controllable enhanced dragging of light in ultradispersive media
Article discussing research on the controllable enhanced dragging of light in ultradispersive media
Frequency up-conversion in Lasing Without Inversion
This article suggests the possibility of frequency up-conversion in lasing without inversion
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Effects of Quantum Coherence and Interference
Quantum coherence and interference (QCI) is a phenomenon that takes place in all multi-level atomic systems interacting with multiple lasers. In this work QCI is used to create several interesting effects like lasing without inversion (LWI), controlling group velocity of light to extreme values, controlling the direction of propagation through non-linear phase matching condition and for controlling the correlations in field fluctuations. Controlling group velocity of light is very interesting because of many novel applications it can offer. One of the unsolved problems in this area is to achieve a slow and fast light which can be tuned continuously as a function of frequency. We describe a method for creation of tunable slow and fast light by controlling intensity of incident laser fields using QCI effects. Lasers are not new to the modern world but an extreme ultra-violet laser or a x-ray laser is definitely one of the most desirable technologies today. Using QCI, we describe a method to realize lasing at high frequencies by creating lasing without inversion. Role of QCI in creating correlations and anti-correlations, which are generated by vacuum fluctuations, in a three level lambda system coupled to two strong fields is discussed