ترغب بنشر مسار تعليمي؟ اضغط هنا

Quantum theory for spatial motion of polaritons in inhomogeneous fields

31   0   0.0 ( 0 )
 نشر من قبل Lan Zhou
 تاريخ النشر 2008
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

Polaritons are the collective excitations of many atoms dressed by resonant photons, which can be used to explain the slow light propagation with the mechanism of electromagnetically induced transparency. As quasi-particles, these collective excitations possess the typical feature of the matter particles, which can be reflected and deflected by the inhomogeneous medium in its spatial motion with some velocity. In this paper we develop a quantum theory to systematically describe the spatial motion of polaritons in inhomogeneous magnetic and optical fields. This theoretical approach treats these quasi-particles through an effective Schr{o}dinger equation with anisotropic depression that the longitudinal motion is like a ultra-relativistic motion of a slow light velocity while the transverse motion is of non-relativity with certain effective mass. We find that, after passing through the EIT medium, the light ray bends due to the spatial-dependent profile of external field. This phenomenon explicitly demonstrates the exotic corpuscular property of polaritons with anisotropic nature.


قيم البحث

اقرأ أيضاً

Recently Drummond and Hillery [Phys. Rev.A 59, 691(1999)] presented a quantum theory of dispersion based on the analysis of a coupled system of the electromagnetic field and atoms in the multipolar QED formulation. The theory has led to the explicit mode-expansions for various field-operators in a homogeneous medium characterized by an arbitrary number of resonant transitions with different frequencies. In this Comment, we drawn attention to a similar multipolar study by Juzeliunas [Phys. Rev.A 53, 3543 (1996); 55, 929 (1997)] on the field quantization in a discrete molecular (or atomic) medium. A comparative analysis of the two approaches is carried out, highlighting both common and distinctive features.
We develop an effective field theory (EFT) to describe the few- and many-body propagation of one dimensional Rydberg polaritons. We show that the photonic transmission through the Rydberg medium can be found by mapping the propagation problem to a no n-equilibrium quench, where the role of time and space are reversed. We include effective range corrections in the EFT and show that they dominate the dynamics near scattering resonances in the presence of deep bound states. Finally, we show how the long-range nature of the Rydberg-Rydberg interactions induces strong effective $N$-body interactions between Rydberg polaritons. These results pave the way towards studying non-perturbative effects in quantum field theories using Rydberg polaritons.
47 - Luca Sapienza 2007
The strong coupling between an intersubband excitation in a quantum cascade structure and a photonic mode of a planar microcavity has been detected by angle-resolved photovoltaic measurements. A typical anticrossing behavior, with a vacuum-field Rabi splitting of 16 meV at 78K, has been measured, for an intersubband transition at 163 meV. These results show that the strong coupling regime between photons and intersubband excitations can be engineered in a quantum cascade opto-electronic device. They also demonstrate the possibility to perform angle-resolved mid-infrared photodetection and to develop active devices based on intersubband cavity polaritons.
We study the collective effects that emerge in waveguide quantum electrodynamics where several (artificial) atoms are coupled to a one-dimensional superconducting transmission line. Since single microwave photons can travel without loss for a long di stance along the line, real and virtual photons emitted by one atom can be reabsorbed or scattered by a second atom. Depending on the distance between the atoms, this collective effect can lead to super- and subradiance or to a coherent exchange-type interaction between the atoms. Changing the artificial atoms transition frequencies, something which can be easily done with superconducting qubits (two levels artificial atoms), is equivalent to changing the atom-atom separation and thereby opens the possibility to study the characteristics of these collective effects. To study this waveguide quantum electrodynamics system, we extend previous work and present an effective master equation valid for an ensemble of inhomogeneous atoms driven by a coherent state. Using input-output theory, we compute analytically and numerically the elastic and inelastic scattering and show how these quantities reveal information about collective effects. These theoretical results are compatible with recent experimental results using transmon qubits coupled to a superconducting one-dimensional transmission line [A.~F.~van Loo {it et al.}].
We demonstrate that intersubband (ISB) polaritons are robust to inhomogeneous effects originating from the presence of multiple quantum wells (MQWs). In a series of samples that exhibit mid-infrared ISB absorption transitions with broadenings varying by a factor of 5 (from 4 meV to 20meV), we have observed polariton linewidths always lying in the 4 - 7 meV range only. We have experimentally verified the dominantly inhomogeneous origin of the broadening of the ISB transition, and that the linewidth reduction effect of the polariton modes persists up to room-temperature. This immunity to inhomogeneous broadening is a direct consequence of the coupling of the large number of ISB oscillators to a single photonic mode. It is a precious tool to gauge the natural linewidth of the ISB plasmon , that is otherwise masked in such MQWs system , and is also beneficial in view of perspective applications such as intersubband polariton lasers.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا