Topic
Atomic coherence
About: Atomic coherence is a research topic. Over the lifetime, 877 publications have been published within this topic receiving 29395 citations.
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TL;DR: In this article, the second-order coherence of a dilute, interacting Bose gas of magnetically-trapped atoms at temperatures below the critical temperature T 0 for Bose-Einstein condensation was determined.
Abstract: For a dilute, interacting Bose gas of magnetically-trapped atoms at temperatures below the critical temperature T0 for Bose-Einstein condensation, we determine the second-order coherence function g(2)(r1, r2) within the framework of a finite-temperature quantum field theory. We show that, because of the different spatial distributions of condensate and thermal atoms in the trap, g(2)(r1, r2) does not depend on |r1 - r2| alone. This means that the experimental determinations of g(2) reported to date give only its spatial average. Such an average may underestimate the degree of coherence attainable in an atom laser by judicious engineering of the output coupler.
15 citations
TL;DR: The reason for the suppression of the coherence effect in open transitions is explained using an analytical calculation of the spectra for a simple V-type three-level atomic system.
Abstract: We present a theoretical and experimental study of electromagnetically induced transparency (EIT) in V-type systems of 87Rb atoms. We calculate accurate lineshapes of V-type EIT spectra by solving density matrix equations considering all the magnetic sublevels involved. The calculated spectra demonstrate consistency with the experimental results. We identify the coherence effect in the calculated EIT spectra, and determine that the coherence effect exists only in the cycling transition. We explain the reason for the suppression of the coherence effect in open transitions using an analytical calculation of the spectra for a simple V-type three-level atomic system.
15 citations
TL;DR: Using the system, it is shown that a photonic stop band can exist on one side away from the resonance point in ultracold atomic gas, while there is an enhanced absorption at resonance and small reflection around it in the thermal atomic gas.
Abstract: We theoretically study the transmission and reflection of the probe travelling wave in an electromagnetically induced absorption grating (EIG), which is created in a three-level Λ-type atomic system when the coupling field is a standing wave. Using the system, we show that a photonic stop band can exist on one side away from the resonance point in ultracold atomic gas, while there is an enhanced absorption at resonance and small reflection around it in the thermal atomic gas. Because our method can deal with such two cases, it is helpful to further understand the effects of the Doppler effect on atomic coherence and interference.
15 citations
TL;DR: In this article, a general model for an atomic memory using ultra-short pulses of light, which allows both spatial and temporal multimode storage, is presented, which is valid for any frequency detuning, from the resonant case to the Raman case, and allows a detailed optimization of the memory efficiency.
Abstract: We present a general model for an atomic memory using ultra-short pulses of light, which allows both spatial and temporal multimode storage. The process involves the storage of a faint quantum light pulse into the spin coherence of the ground state of Lambda-type 3-level atoms, in the presence of a strong driving pulse. Our model gives a full description of the evolution of the field and of the atomic coherence in space and time throughout the writing and the read-out processes. It is valid for any frequency detuning, from the resonant case to the Raman case, and allows a detailed optimization of the memory efficiency.
15 citations
TL;DR: Ostermann et al. as discussed by the authors proposed a modified Ramsey spectroscopy technique employing slowly decaying states for quantum metrology applications using dense ensembles, which achieved a better scaling of the frequency sensitivity with interrogation time than for noninteracting particles.
Abstract: We study a modified Ramsey spectroscopy technique employing slowly decaying states for quantum metrology applications using dense ensembles. While closely positioned atoms exhibit super-radiant collective decay and dipole-dipole induced frequency shifts, recent results [L. Ostermann, H. Ritsch, and C. Genes, Phys. Rev. Lett. 111, 123601 (2013)] suggest the possibility to suppress such detrimental effects and achieve an even better scaling of the frequency sensitivity with interrogation time than for noninteracting particles. Here we present an in-depth analysis of this ``protected subspace Ramsey technique'' using improved analytical modeling and numerical simulations including larger three-dimensional (3D) samples. Surprisingly we find that using subradiant states of $N$ particles to encode the atomic coherence yields a scaling of the optimal sensitivity better than $1/\sqrt{N}$. Applied to ultracold atoms in 3D optical lattices we predict a precision beyond the single atom linewidth.
15 citations