Proposed search for an electric-dipole moment using laser-cooled 171^{171}Yb atoms

We propose an experiment to search for a permanent atomic electric-dipole moment (EDM) using laser-cooled $^{171}$Yb atoms launched in an atomic fountain. A uniform B field sets the quantization axis, and the Ramsey separated-oscillatory-fields method is used to measure the Zeeman precession frequency of the atoms. Laser beams of appropriate polarization are used for preparation and detection in a given magnetic sublevel. The signature of an EDM is a shift in the Ramsey resonance correlated with application of a large E field. The precision is expected to be at least 20 times better than current limits because the use of a cold atomic beam allows application of E field 10 times larger than in a vapor cell, and the interaction time with the E field is 200 times larger compared to a thermal beam. The leading source of systematic error in beam experiments, the (E x v/c) motional magnetic field, is reduced considerably because of the near-perfect reversal of velocity between up and down trajectories through the E-field region.Comment: 7 pages, 3 figure

What is a photon?

We discuss the absorber theory of radiation as put forward by Wheeler and Feynman. We show that it gives a better understanding of the photon compared to the usual quantum electrodynamics (QED) picture.Comment: 9 page

Sub- and super-luminal light propagation using a Rydberg state

We present a theoretical study to investigate sub- and super-luminal light propagation in a rubidium atomic system consisting of a Rydberg state by using density matrix formalism. The analysis is performed in a 4-level vee+ladder system interacting with a weak probe, and strong control and switching fields. The dispersion and absorption profiles are shown for stationary atoms as well as for moving atoms by carrying out Doppler averaging at room temperature. We also present the group index variation with control Rabi frequency and observe that a transparent medium can be switched from sub- to super-luminal propagation in the presence of switching field. Finally, the transient response of the medium is discussed, which shows that the considered 4-level scheme has potential applications in absorptive optical switching.Comment: 12 pages, 6 figure

Study of a four-level system in vee + ladder configuration

We present the results of a theoretical study of a four-level atomic system in vee + ladder configuration using a density matrix analysis. The absorption and dispersion profiles are derived for a weak probe field and for varying strengths of the two strong control fields. For specificity, we choose energy levels of $^{87}$Rb, and present results for both stationary atoms and moving atoms in room temperature vapor. An electromagnetically induced absorption (EIA) peak with negative dispersion is observed at zero probe detuning when the control fields have equal strengths, which switches to electromagnetically induced transparency (EIT) with positive dispersion (due to splitting of the EIA peak) when the control fields are unequal. There is significant linewidth narrowing in thermal vapor.Comment: 6 pages, 4 figure

Economic Liberalization and Rural Land and Labour Markets in India: A Study

The paper examines the rural land and labour markets in the context of economic liberalization in India. Land and labour are the two fundamental resources available to the rural people for income generation. The access to land and to employment for labour become basic determinants of well-being for the rural households. Reforms are often seen as hostile to rural areas and the poor, although they should be beneficial not only for overall growth, but also rural growth and poverty alleviation. The study based on primary household data examines the land and labour markets in the reform period and the underlying linkages of these to different characteristics of the household. The study finds that over the reform period in India the land markets are leading to less landlessness rather than more, and growth in marginal and medium farm sizes rather than large. Lease markets are leading to operated land in more hands. Land purchase behaviour is related to less land, more education, greater crop diversification, and higher crop and livestock revenues. Leasing-in is also related to many of the same variables and is showing great diversity in lease agreements involving outputs, inputs and rent. Labour-employment is showing diversity of occupations but the primary dependence on agriculture is still about 80 percent. There has been some change in the occupational structure. Nonfarm employment is associated with higher overall employment. Own-farm employment is strongly related to crop diversification and livestock activity; other farm employment to number of male and female family members and irrigation; and non-farm employment to education. Broadly, liberalization does not show adverse consequences but rather some positive impact on rural land and labour markets.Reform, Land, Labour, Development, Poverty, Labor and Human Capital, Land Economics/Use,