اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدInfluence of chirping the Raman lasers in an atom gravimeter: phase shifts due to the Raman light shift and to the finite speed of light
57
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We present here an analysis of the influence of the frequency dependence of the Raman laser light shifts on the phase of a Raman-type atom gravimeter. Frequency chirps are applied to the Raman lasers in order to compensate gravity and ensure the resonance of the Raman pulses during the interferometer. We show that the change in the Raman light shift when this chirp is applied only to one of the two Raman lasers is enough to bias the gravity measurement by a fraction of $mu$Gal ($1~mu$Gal~=~$10^{-8}$~m/s$^2$). We also show that this effect is not compensated when averaging over the two directions of the Raman wavevector $k$. This thus constitutes a limit to the rejection efficiency of the $k$-reversal technique. Our analysis allows us to separate this effect from the effect of the finite speed of light, which we find in perfect agreement with expected values. This study highlights the benefit of chirping symmetrically the two Raman lasers.
قيم البحث
اقرأ أيضاً
We study propagation effects due to the finite speed of light in ionization of extended systems. We present a general quantitative theory of these effects and show under which conditions such effects should appear. The finite speed of light propagati
on effects are encoded in the non-dipole terms of the time-dependent Shrodinger equation and display themselves in the photoelectron momentum distribution projected on the molecular axis. Our numerical modeling for the Hp molecular ion and the Ne dimer shows that the finite light propagation time from one atomic center to another can be accurately determined in a table top laser experiment which is much more readily affordable than an earlier synchrotron measurement by Grundmann {em et al} [Science 370, 339 (2020)]
We study the influence of off-resonant two photon transitions on high precision measurements with atom interferometers based on stimulated Raman transitions. These resonances induce a two photon light shift on the resonant Raman condition. The impact
of this effect is investigated in two highly sensitive experiments: a gravimeter and a gyroscope-accelerometer. We show that it can lead to significant systematic phase shifts, which have to be taken into account in order to achieve best performances in term of accuracy and stability.
When polarized light is absorbed by an atom, the excited atomic system carries information about the initial polarization of light. For the light that carries an orbital angular momentum, or the twisted light, the polarization states are described by
eight independent parameters, as opposed to three Stokes parameters for plane waves. We use a parameterization of the spin-density matrix of the twisted light in terms of vector and tensor polarization, in analogy with massive spin-1 particles, and derive formulae that define atoms response to specific polarization components of the twisted light. It is shown that for dipole ($Sto P$) atomic transitions, the atoms polarization is in one-to-one correspondence with polarization of the incident light; this relation is violated, however, for the transitions of higher multipolarity ($Sto D$, $Sto F$, etc.) We pay special attention to contributions of the longitudinal electric field into the matrix elements of atomic transitions.
We present here a detailed study of the influence of the transverse motion of the atoms in a free-fall gravimeter. By implementing Raman selection in the horizontal directions at the beginning of the atoms free fall, we characterize the effective vel
ocity distribution, ie the velocity distribution of the detected atom, as a function of the laser cooling and trapping parameters. In particular, we show that the response of the detection induces a pronounced asymetry of this effective velocity distribution that depends not only on the imbalance between molasses beams but also on the initial position of the displaced atomic sample. This convolution with the detection has a strong influence on the averaging of the bias due to Coriolis acceleration. The present study allows a fairly good understanding of results previously published in {it Louchet-Chauvet et al., NJP 13, 065025 (2011)}, where the mean phase shift due to Coriolis acceleration was found to have a sign different from expected.
This article is dedicated to the following class of problems. Start with an $Ntimes N$ Hermitian matrix randomly picked from a matrix ensemble - the reference matrix. Applying a rank-$t$ perturbation to it, with $t$ taking the values $1le t le N$, we
study the difference between the spectra of the perturbed and the reference matrices as a function of $t$ and its dependence on the underlying universality class of the random matrix ensemble. We consider both, the weaker kind of perturbation which either permutes or randomizes $t$ diagonal elements and a stronger perturbation randomizing successively $t$ rows and columns. In the first case we derive universal expressions in the scaled parameter $tau=t/N$ for the expectation of the variance of the spectral shift functions, choosing as random-matrix ensembles Dysons three Gaussian ensembles. In the second case we find an additional dependence on the matrix size $N$.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
