Abstract
AbstractThe quadrupole and higher order anisotropies in the cosmic microwave background radiation has been discovered by COBE [1] and many other experiments[2]. Here we ask the question: Are the fundamental laws of our Universe also anisotropic? This is a valid question since many people, at present, believe that the early Universe may have gone through phase transitions. If yes, may spin states sense these anisotropies? In this thesis we address to the question whether our laboratory is the same for different spin states of electron. In the classical context, the potential anisotropy could be related to Mach's principle and depend on the matter and spin distribution of our Universe. In this aspect, it is in the long tradition of Hughes-Drever experiments[3]. In the modern context, the motion of the earth through the cosmic neutrino background, or certain kinds of vacuum states, produces a term of the form gσ•v in the energy of an electron. Here g is a constant value, σ is the electron spin and v is the velocity of the earth through the cosmic neutrion background or certain kinds of vacuum states. To search for such a term or a term like gσ•n where n is a particular direction in the Universe, Phillips[4] used a traditional fixed torsion balance carrying a transversely polarized magnet to search for a sinusoidal oscillation of the pendulum with a period of one sidereal day. Our laboratory[5] continued this effort and improved the sensitivity by a factor of 3.For last 4 years, we have been developing a rotatable torsion balance carrying a magnetically shielded transversely spin-polarized ferrimagnetic Dy_{6}Fe_{23} mass for the test of spatial anisotropy with a period of about 1 hour with the period shortened the data taking time and noise are much reduced. With earth's rotation, the two senses (clockwise and counterclockwise) of torsion balance rotation is modulated differently. With our present data-taking and noise substraction algorithm, this double modulation scheme (torsion-balance rotation plus earth rotation) can detect the anisotropic energy splitting of spin states of electrons in the axial direction of earth rotation also. Analysis of accumulated results of our present experiments gives an improved limit of energy splitting of 5.7 ×10^{-20} eV for transverse direction, a 50-fold improvement compared to fixed torsion balnce, and the splitting of spin states of an electron in the plane normal to the earth rotation axis and a new limit of 9.7× 10^{-19} eV for axial direction.