اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدSpontaneous creation and persistence of ground-state coherence in a resonantly driven intra-cavity atomic ensemble
276
0
0.0
(
0
)
تأليف
D. G. Norris
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The spontaneous creation and persistence of ground-state coherence in an ensemble of intracavity Rb atoms has been observed as a quantum beat. Our system realizes a quantum eraser, where the detection of a first photon prepares a superposition of ground-state Zeeman sublevels, while detection of a second erases the stored information. Beats appear in the time-delayed photon-photon coincidence rate (intensity correlation function). We study the beats theoretically and experimentally as a function of system parameters, and find them remarkably robust against perturbations such as spontaneous emission. Although beats arise most simply through single-atom-mediated quantum interference, scattering pathways involving pairs of atoms interfere also in our intracavity experiment. We present a detailed model which identifies all sources of interference and accounts for experimental realities such as imperfect pre-pumping of the atomic beam, cavity birefringence, and the transit of atoms across the cavity mode.
قيم البحث
اقرأ أيضاً
We study an array of dissipative tunnel-coupled cavities, each interacting with an incoherently pumped two-level emitter. For cavities in the lasing regime, we find correlations between the light fields of distant cavities, despite the dissipation an
d the incoherent nature of the pumping mechanism. These correlations decay exponentially with distance for arrays in any dimension but become increasingly long ranged with increasing photon tunneling between adjacent cavities. The interaction-dominated and the tunneling-dominated regimes show markedly different scaling of the correlation length which always remains finite due to the finite photon trapping time. We propose a series of observables to characterize the spontaneous build-up of collective coherence in the system.
We present a fast and Quasideterministic protocol for the production of single ions and electrons from a cloud of laser cooled atoms. The approach is based on a two-step process where first a single Rydberg atom is photo-excited from a dipole-blockad
e configuration and subsequently ionized by an electric field pulse. We theoretically describe these excitation-ionization cycles via dynamical quantum maps and observe a rich behavior of the ionization dynamics as a function of laser Rabi frequency, pulse duration and particle number. Our results show that a fast sequential heralded production of single charged particles is achievable even from an unstructured and fluctuating atomic ensemble.
Quantum light-matter interfaces, based upon ensembles of cold atoms or other quantum emitters, are a vital platform for diverse quantum technologies and the exploration of fundamental quantum phenomena. Most of our understanding and modeling of such
systems are based upon macroscopic theories, wherein the atoms are treated as a smooth, quantum polarizable medium. Although it is known that such approaches ignore a number of microscopic details, such as the granularity of atoms, dipole-dipole interactions and multiple scattering of light, the consequences of such effects in practical settings are usually mixed with background macroscopic effects and difficult to quantify. In this work we demonstrate a time-domain method to measure microscopically-driven optical effects in a background-free fashion, by transiently suppressing the macroscopic dynamics. With the method, we reveal a microscopic dipolar dephasing mechanism that generally limits the lifetime of the optical spin-wave order in a random gas. Theoretically, we show the dephasing effect emerges from the strong resonant dipole interaction between close-by atomic pairs.
We analyze a similar scheme for producing light-mediated entanglement between atomic ensembles, as first realized by Julsgaard, Kozhekin and Polzik [Nature {bf 413}, 400 (2001)]. In the standard approach to modeling the scheme, a Holstein-Primakoff a
pproximation is made, where the atomic ensembles are treated as bosonic modes, and is only valid for short interaction times. In this paper, we solve the time evolution without this approximation, which extends the region of validity of the interaction time. For short entangling times, we find this produces a state with similar characteristics as a two-mode squeezed state, in agreement with standard predictions. For long entangling times, the state evolves into a non-Gaussian form, and the two-mode squeezed state characteristics start to diminish. This is attributed to more exotic types of entangled states being generated. We characterize the states by examining the Fock state probability distributions, Husimi $Q$ distributions, and non-local entanglement between the ensembles. We compare and connect several quantities obtained using the Holstein-Primakoff approach and our exact time evolution methods.
Quantum coherence and interference effects in atomic and molecular physics has been extensively studied due to intriguing counterintuitive physics and potential important applications. Here we present one such application of using quantum coherence t
o generate and enhance gain in extreme ultra-violet(XUV)(@58.4nm in Helium) and infra-red(@794.76nm in Rubidium) regime of electromagnetic radiation. We show that using moderate external coherent drive, a substantial enhancement in the energy of the lasing pulse can be achieved under optimal conditions. We also discuss the role of coherence. The present paper is intended to be pedagogical on this subject of coherence-enhanced lasing.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
