arXiv subjects

Dam Quang Nam

Publications and source records attributed to Dam Quang Nam.

3 recordsLinked to original sources

arXiv2024

TDI noises transfer functions for LISA

The LISA mission is the future space-based gravitational wave (GW) observatory of the European Space Agency. It is formed by 3 spacecraft exchanging laser beams in order to form multiple real and virtual interferometers. The data streams to be used in order to extract the large number and variety of GW sources are Time-Delay Interferometry (TDI) data. One important processing to produce these data is the TDI on-ground processing which recombines multiple interferometric on-board measurements to remove certain noise sources from the data such as laser frequency noise or spacecraft jitter. The LISA noise budget is therefore expressed at the TDI level in order to account for the different TDI transfer functions applied for each noise source and thus estimate their real weight on mission performance. In order to derive a usable form of these transfer functions, a model of the beams, the measurements, and TDI have been developed, and several approximation have been made. A methodology for such a derivation has been established, as well as verification procedures. It results in a set of transfer functions, which are now used by the LISA project, in particular in its performance model. Using these transfer functions, realistic noise curves for various instrumental configurations are provided to data analysis algorithms and used for instrument design.

gr-qc↗

arXiv2023

Electroweak phase transition via Dilaton in Two-Time Physics

The Two-time model (2T model) has six dimensions with two dimensions of time, has a Dilaton particle that makes the symmetry breaking differently from the Standard Model. Assuming a soft break of $SP(2,R)$ symmetry, the 2T extension can give a suitable picture of the matter-antimatter asymmetry by the Baryogenesis scenario. By reducing the 2T metric to the Minkowski metric (1T metric) and using a new form of Dilaton potential, we consider the electroweak phase transition picture in the 2T model with the Dilaton as a trigger. Our analysis shows that Electroweak Phase Transition (EWPT) is a first-order phase transition at the $200$ GeV scale, its strength is about $1 - 3.08$ and the mass of Dilaton is in the interval $[345,625]$ GeV. Therefore, the 2T-model indirectly suggests that extra-dimension can also be a source of EWPT.

hep-ph↗

arXiv2023

LISA Dynamics & Control: Closed-loop Simulation and Numerical Demonstration of Time Delay Interferometry

The Laser Interferometer Space Antenna (LISA), space-based gravitational wave observatory involves a complex multidimensional closed-loop dynamical system. Its instrument performance is expected to be less efficiently isolated from platform motion than was its simpler technological demonstrator, LISA Pathfinder. It is of crucial importance to understand and model LISA dynamical behavior accurately to understand the propagation of dynamical excitations through the response of the instrument down to the interferometer data streams. More generally, simulation of the system allows for the preparation of the processing and interpretation of in-flight metrology data. In this work, we present a comprehensive mathematical modeling of the closed-loop system dynamics and its numerical implementation within the LISA Consortium simulation suite. We provide, for the first time, a full time-domain numerical demonstration of post-processing Time Delay Interferometer techniques combining multiple position measurements with realistic control loops to create a synthetic Michelson interferometer. We show that in the absence of physical coupling to spacecraft and telescope motion (through tilt-to-length, stiffness and actuation cross-talk) the effect of noisy spacecraft motion is efficiently suppressed to a level below the noise originating in the rest of the instrument.

gr-qc↗