Ground testing of release impulse for the aluminum test mass based on the compound pendulum

In the space gravitational wave detection program, the locking and releasing of test mass is one of the key technologies. The test mass is locked in during the launch phase of the spacecraft and then released during the scientific exploration phase, allowing it to go into free fall. Among them, the residual release impulse of the test mass is required to be in the order of magnitude of 10-5 kg m/s, so that the test mass can be trapped by the electrostatic feedback control. Based on the above content, a compound pendulum is built to measure the release impulse of the test mass. The test mass is locked by two thimbles in the opposite positions, and the release impulse is obtained by the swing of the pendulum. When the aluminum test mass is locked and released by the aluminum and the stainless steel thimbles, the release impulse and its uncertainty are in the order of magnitude of 10-5 kg m/s and 10-7 kg m/s, respectively. The double-thimble locking and releasing experiment based on the compound pendulum provides a feasible measurement scheme for the test of the release impulse in Tianqin project. 97 Wave function of the universe in the presence of trans-Planckian censorship Indian Association for the Cultivation of Science The wave function for a closed de Sitter universe has been computed, demanding consistency with the recently proposed Trans-Planckian Censorship Conjecture (TCC). We extend the Einstein-Hilbert action to contain a complex-valued term which provides an exponentially decaying weight for the geometries violating TCC in the Lorentzian path integral sum while working in the minisuperspace approach to quantum cosmology. This postulated modification suppresses the probability of evolution of the universe into configurations that violate TCC. We show that due to the presence of this suppression factor, the Hubble rate of the universe at the end of the inflation gets subdued and assumes a value less than what is expected classically. Moreover, the consequences of this quantum gravity motivated correction in the primordial power spectrum are discussed as well. Strong electromagnetic and gravitational field physics: From laboratories to early Universe / 98 Non-linear media in weakly curved spacetime: optical solitons and probe pulses for gravimetry 1 Humboldt Universität zu Berlin That light propagating in a gravitational field gets frequency-shifted is one of the basic consequences of any metric theory of gravity rooted in the equivalence principle. At the same time, also a time dependent material’s refractive index can frequency-shift light propagating in it. The mathematical analogy between the two effects is such that the latter has been used to study the optical analogue of a black-hole spacetime. Here, we combine these two effects by showing that light propagation in non-linear media in the presence of a moving refractive index perturbation can lead to a gravity-dependent blueshift. We find that the predicted blueshift surpasses the gravitational redshift even if the medium is considered to be perfectly stiff. In realistic scenarios, by far the strongest frequency shift arises due to the deformation of the dielectric medium and the corresponding photoelastic change of refractive index. This has the potential to facilitate optical sensing of small gravity gradients.