No Arabic abstract
The recent realization that atom interferometers (AIs) can be used to test the gravitational redshift tests has proven to be controversial in some quarters. Here, we address the issues raised against the interpretation of AIs as redshift tests, reaffirming the fact that Mueller et al. [Nature 463, 926 (2010)] indeed report a gravitational redshift test.
We show that Wolf et al.s 2011 analysis in Class. Quant. Grav. v28, 145017 does not support their conclusions, in particular that there is no redshift effect in atom interferometers except in inconsistent dual Lagrangian formalisms. Wolf et al. misapply both Schiffs conjecture and the results of their own analysis when they conclude that atom interferometers are tests of the weak equivalence principle which only become redshift tests if Schiffs conjecture is invalid. Atom interferometers are direct redshift tests in any formalism.
We realize and model a Rydberg-state atom interferometer for measurement of phase and intensity of radio-frequency (RF) electromagnetic waves. A phase reference is supplied to the atoms via a modulated laser beam, enabling atomic measurement of the RF waves phase without an external RF reference wave. The RF and optical fields give rise to closed interferometric loops within the atoms internal Hilbert space. In our experiment, we construct interferometric loops in the state space ${ 6P_{3/2}, 90S_{1/2}, 91S_{1/2}, 90P_{3/2} }$ of cesium and employ them to measure phase and intensity of a 5 GHz RF wave in a room-temperature vapor cell. Electromagnetically induced transparency on the $6S_{1/2}$ to $6P_{3/2}$ transition serves as an all-optical interferometer probe. The RF phase is measured over a range of $pi$, and a sensitivity of 2 mrad is achieved. RF phase and amplitude measurements at sub-millimeter optical spatial resolution are demonstrated.
We propose new multi-dimensional atom optics that can create coherent superpositions of atomic wavepackets along three spatial directions. These tools can be used to generate light-pulse atom interferometers that are simultaneously sensitive to the three components of acceleration and rotation, and we discuss how to isolate these inertial components in a single experimental shot. We also present a new type of atomic gyroscope that is insensitive to parasitic accelerations and initial velocities. The ability to measure the full acceleration and rotation vectors with a compact, high-precision, low-bias inertial sensor could strongly impact the fields of inertial navigation, gravity gradiometry, and gyroscopy.
We investigate wave optical imaging of black holes with Hawking radiation. The spatial correlation function of Hawking radiation is expressed in terms of transmission and reflection coefficients for scalar wave modes and evaluated by taking summation over angular qunatum numbers numerically for the Unruh-Hawking state of the Kerr-de Sitter black hole. Then wave optical images of evaporating black hole are obtained by Fourier transformation of the spatial correlation function. For short wavelength, the image of the black hole with the outgoing mode of the Unruh-Hawking state looks like a star with its surface is given by the photon sphere. It is found that interference between incoming modes from the cosmological horizon and reflected modes due to scattering of the black hole can enhance brightness of images in the vicinity of the photon sphere. For long wavelenth, whole field of view becomes bright and emission region of Hawking radiation cannot be identifed.
We have studied the interference of degenerate quantum gases in a vertical optical lattice. The coherence of the atoms leads to an interference pattern when the atoms are released from the lattice. This has been shown for a Bose-Einstein condensate in early experiments. Here we demonstrate that also for fermions an interference pattern can be observed provided that the momentum distribution is smaller then the recoil momentum of the lattice. Special attention is given to the role of interactions which wash out the interference pattern for a condensate but do not affect a spin polarized Fermi gas, where collisions at ultra cold temperatures are forbidden. Comparing the interference of the two quantum gases we find a clear superiority of fermions for trapped atom interferometry.