Xin-Lei Zhao | Searcharxiv

arXiv2026

Tidal Love numbers of multi-state Boson stars

In this paper, we calculate the tidal Love numbers of multi-state boson stars (MSBSs) composed of ground state and first excited state complex scalar fields. Under synchronized and nonsynchronized frequency conditions, the background solutions of MSBSs are classified into single-branch and double-branch types. The field functions, ADM mass, and binding energy of different solutions are discussed. We then calculate the quadrupolar ($\ell=2$) electric and magnetic tidal Love numbers for branches containing stable solutions. Our results show that the electric tidal Love numbers are initially positive and then suddenly transition to negative values. This phenomenon occurs when the parameters satisfy $\tildeμ_1 > 0.891$ or $\tildeω_0 > 0.777$; for smaller values of these parameters, the electric Love numbers remain positive. The magnetic tidal Love numbers are always negative, with absolute values smaller than those of the electric tidal Love numbers.

gr-qc↗

arXiv2026

Gravitational-wave response functions for space-borne detectors based on multiple geometric time-delay interferometry links

The primary challenge for space-borne gravitational wave (GW) detectors lies in extracting the weak GW signal from instrumental noise that exceeds the signal level by many orders of magnitude. Time-delay interferometry (TDI) addresses this by suppressing the dominant laser phase noise through recombination of time-delayed measurement data. The detector's response to a GW signal is represented in the frequency domain by a response function. Currently, the GW signal response is first expressed in terms of the Doppler frequency shift in a single detection arm, and this formulation is then incorporated into specific TDI combinations to derive the corresponding response function. This paper introduces a generalized formulation for TDI combinations based on multiple geometric links. By extending the representation of the laser Doppler frequency shift to include various geometric configurations, such as round-trip and non-round-trip links, we reformulate 45 second-generation TDI combinations. For several of these, the new formulation significantly streamlines their mathematical expressions and enhances physical clarity. Our results demonstrate that the proposed link-mapping rules not only enable efficient construction of response functions for these TDI combinations but also reduce computational complexity. This approach provides a reliable theoretical and algorithmic foundation for data processing in future space-borne GW missions.

gr-qc↗