Figure 2 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
The PSD P n ( f ) for different channels. The solid and dashed lines denote the X and A channels, respectively. We use the red/blue lines to label the LISA and TianQin.
Source publication
While general relativity predicts only two tensor modes for gravitational-wave (GW) polarization, general metric theories of gravity allow for up to four additional modes, including two vector and two scalar modes. Observing the polarization modes of GWs could provide a direct test of the modified gravity. The stochastic GW background (SGWB), which...
Context in source publication
Similar publications
We investigate how quantum coincidence interferometry is affected by a controllable manipulation of transverse wave-vectors in type-II parametric down conversion using adaptive optics techniques. In particular, we discuss the possibility of spatial walk-off compensation in quantum interferometry and a new effect of even-order spatial aberration can...
We present for the first time Very-Long-Baseline Interferometry images of the radio galaxy Cygnus A at the frequency of $86$ $\rm GHz$. Thanks to the high spatial resolution of only ${\sim}200$ Schwarzschild radii ($R_{\bf S}$), such observations provide an extremely detailed view of the nuclear regions in this archetypal object and allow us to der...
Seismic interferometry can obtain a new record by correlating original response received at two different stations. In the record, one station acts as the virtual source, while the other is regarded as the receiver. However, conventional cross-correlation interferometry calculations may yield inaccurate imaging results for virtual source records du...
To achieve real-time phase detection, this paper presents a fast and precise spatial carrier phase-shifting interferometry based on the dynamic mode decomposition strategy. The algorithm initially produces a series of phase-shifted sub-interferograms with the aid of a spatial carrier interferogram. Subsequently, the measured phases are derived with...
This study investigates the ablation threshold fluence and power dependence of ablation process in CoCuFeNiMnMox (x = 0.5, 1.0, and 1.5) high-entropy alloys under ultraviolet nanosecond laser pulses. The ablation threshold value, a critical parameter determining the minimum energy density required for laser material removal, is explored in-depth. M...
Citations
... With a preliminary study with Bayes method, the constraint with TianQin on the amplitudes is about a few percent [350]. The possibility of using SGWB to constrain the extra polarization modes has been studied in [351,352]. ...
The exploration of the surrounding world and the universe is an important theme in the legacy of humankind. The detection of gravitational waves is adding a new dimension to this grand effort. What are the fundamental physical laws governing the dynamics of the universe? What is the fundamental composition of the universe? How has the universe evolved in the past and how will it evolve in the future? These are the basic questions that press for answers. The space-based gravitational wave detector TianQin will tune in to gravitational waves in the millihertz frequency range ( Hz, to be specific), opening a new gravitational wave spectrum window to explore many of the previously hidden sectors of the universe. TianQin will discover many astrophysical systems, populating the universe at different redshifts: some will be of new types that have never been detected before, some will have very high signal-to-noise ratios, and some will have very high parameter estimation precision. The plethora of information collected will bring us to new fronts on which to search for the breaking points of general relativity, the possible violation of established physical laws, the signature of possible new gravitational physics and new fundamental fields, and to improve our knowledge on the expansion history of the universe. In this white paper, we highlight the advances that TianQin can bring to fundamental physics and cosmology.
... In a preliminary study with the Bayes method, the constraint with TianQin on the amplitudes of extra polarization modes has been found to be about a few percent [85]. The possibility of using SGWB to constrain the extra polarization modes has been studied in [86,87]. ...
TianQin is a future space-based gravitational wave observatory targeting the frequency window of Hz Hz. A large variety of gravitational wave sources are expected in this frequency band, including the merger of massive black hole binaries, the inspiral of extreme/intermediate mass ratio systems, stellar-mass black hole binaries, Galactic compact binaries, and so on. TianQin will consist of three Earth orbiting satellites on nearly identical orbits with orbital radii of about km. The satellites will form a normal triangle constellation whose plane is nearly perpendicular to the ecliptic plane. The TianQin project has been progressing smoothly following the ``0123" technology roadmap. In step ``0", the TianQin laser ranging station has been constructed and it has successfully ranged to all the five retro-reflectors on the Moon. In step ``1", the drag-free control technology has been tested and demonstrated using the TianQin-1 satellite. In step ``2", the inter-satellite laser interferometry technology will be tested using the pair of TianQin-2 satellites. The TianQin-2 mission has been officially approved and the satellites will be launched around 2026. In step ``3", i.e., the TianQin-3 mission, three identical satellites will be launched around 2035 to form the space-based gravitational wave detector, TianQin, and to start gravitational wave detection in space.
... Numerous interesting work has been carried out on SGWB detection with the space-based GW detector networks [45][46][47][48][49][50][51][52][53]. Among them, Ref. [45] presents the first quantitative analysis for measuring parity asymmetry in the SGWB by utilizing data streams from the LISA-Taiji detector network. ...
... More general detector networks have been proposed to search for isotropic background signals [47]. Additionally, Bayesian data analysis methods based on the LISA-TianQin network have also been developed [52,53]. Conversely, scant data analysis efforts have been devoted to directly evaluating the parameter estimates and detection limits of the SGWB as of yet. ...
... For the special case of a triangular-shaped GW detector, the cross-correlation method now widely used in ground-based detector networks will not be available [37,[42][43][44]. However, the recent rapid development of mHz space-based GW detectors has made it possible to construct space-based GW detector networks for identifying SGWB from complex noise via crosscorrelation analysis [45][46][47][48][49][50][51][52][53]. ...
The stochastic gravitational wave background (SGWB) is one of the main detection targets for future millihertz space-borne gravitational-wave observatories such as the \ac{LISA}, TianQin, and Taiji. For a single LISA-like detector, a null-channel method was developed to identify the SGWB by integrating data from the A and E channels with a noise-only T channel. However, the noise monitoring channel will not be available if one of the laser interferometer arms fails. By combining these detectors, it will be possible to build detector networks to search for SGWB via cross-correlation analysis.In this work, we developed a Bayesian data analysis method based on \ac{TDI} Michelson-type channel. We then investigate the detectability of the TianQin-LISA detector network for various isotropic SGWB. Assuming a three-month observation, the TianQin-LISA detector network could be able to confidently detect SGWB with energy density as low as , and for power-law, flat and single-peak models, respectively.
... which provides a clear connection between the investigated metric perturbations and the relative motion of test particles. Any detection (or nondetection) of modified behavior following from the analysis of the NMC theory could provide means to further restrict the theory's parameters or even test for its presence [10,11,42,43]. ...
... Additionally, the separation of the η and spatial evolution means that we have no radiative behavior and thus the NMC theory does not predict wavelike evolution for the vector terms in the metric perturbation. The modification of the temporal evolution of the vector sector could provide an opportunity to observationally test the presence of a nonminimal coupling in the gravitational theory [10,42]. However, this would involve obtaining observations at a considerable variety of redshifts and throughout a wide variety of systems in order to draw any solid conclusions. ...
... These terms correspond to longitudinal and breathing modes respectively and lead to distinct behavior from the tensorial þ and × modes [16]. In GR, only the massless spin-2 modes are expected to be present, while some modified theories of gravity predict the existence of the aforementioned scalar modes [10,42]. Particularly, this was already established in the context of minimally and nonminimally coupled fðRÞ theories [18,20,22]. ...
The properties of metric perturbations are determined in the context of an expanding Universe governed by a modified theory of gravity with a non-minimal coupling between curvature and matter. We analyse the dynamics of the 6 components of a general helicity decomposition of the metric and stress-energy perturbations, consisting of scalar, vector and tensor sectors. The tensor polarisations are shown to still propagate luminally, in agreement with recent data from gravitational interferometry experiments, while their magnitude decays with an additional factor sourced by the nonminimal coupling. We show that the production of these modes is associated with a modified quadrupole formula at leading order. The vector perturbations still exhibit no radiative behaviour, although their temporal evolution is found to be modified, with spatial dependence remaining unaffected. We establish that the scalar perturbations can no longer be treated as identical. We investigate the scalar sector by writing the modified model as an equivalent two-field scalar-tensor theory and find the same scalar degrees of freedom as in previous literature. The different sectors are paired with the corresponding polarisation modes, which can be observationally measured by their effects on the relative motion of test particles, thus providing the possibility of testing the modified theory and constraining its parameters.
... which provides a clear connection between the investigated metric perturbations and the relative motion of test particles. Any detection (or non-detection) of modified behaviour following from the analysis of the NMC theory could provide means to further restrict the theory's parameters or even test for its presence [10,11,42,43]. ...
... Additionally, the separation of the η and spatial evolution means that we have no radiative behaviour and thus the NMC theory does not predict wave-like evolution for the vector terms in the metric perturbation. The modification of the temporal evolution of the vector sector could provide an opportunity to observationally test the presence of a nonminimal coupling in the gravitational theory [10,42]. However, this would involve obtaining observations at a considerable variety of redshifts and throughout a wide variety of systems in order to draw any solid conclusions. ...
... These terms correspond to longitudinal and breathing modes respectively and lead to distinct behaviour from the tensorial + and × modes [16]. In GR, only the massless spin-2 modes are expected to be present, while some modified theories of gravity predict the existence of the aforementioned scalar modes [10,42]. Particularly, this was already established in the context of minimally and nonminimally coupled f (R) theories [18,20,22]. ...
The properties of metric perturbations are determined in the context of an expanding Universe governed by a modified theory of gravity with a non-minimal coupling between curvature and matter. We analyse the dynamics of the 6 components of a general helicity decomposition of the metric and stress-energy perturbations, consisting of scalar, vector and tensor sectors. The tensor polarisations are shown to still propagate luminally, in agreement with recent data from gravitational interferometry experiments, while their magnitude decays with an additional factor sourced by the nonminimal coupling. We show that the production of these modes is associated with a modified quadrupole formula at leading order. The vector perturbations still exhibit no radiative behaviour, although their temporal evolution is found to be modified, with spatial dependence remaining unaffected. We establish that the scalar perturbations can no longer be treated as identical. We investigate the scalar sector by writing the modified model as an equivalent two-field scalar-tensor theory and find the same scalar degrees of freedom as in previous literature. The different sectors are paired with the corresponding polarisation modes, which can be observationally measured by their effects on the relative motion of test particles, thus providing the possibility of testing the modified theory and constraining its parameters.
... Given the challenge of distinguishing SGWB from detector noise, cross-correlation method [11][12][13][14][15][16][17][18] and nullchannel method [19][20][21][22] have been proposed. For terrestrial detectors such as ground-based detectors and Pulsar Timing Arrayss (PTAs), cross-correlating data from multiple detectors has been used to filter out noise and isolate potential SGWB signals. ...
Space-borne detectors, including TianQin and Laser Interferometry Space Antenna (LISA), are tasked with the simultaneous observation of Galactic foreground, astrophysical and cosmological stochastic gravitational-wave backgrounds (SGWBs). For the first time, we employ a space-borne detector network to identify the multi-component SGWB. Specifically, we develop a tailored likelihood for cross-correlation detection with such networks. Combined with the likelihood, we use the simulated datasets of the TianQin + LISA network to conduct model selection and parameter estimation. Our results indicate that, after 4 years of operation, the network could detect a single SGWB from either astrophysical or cosmological origins, with an energy density (10 mHz) on the order of , despite the presence of a Galactic foreground. Furthermore, to distinguish the cosmological background from both a Galactic foreground and the expected astrophysical background, the energy density should reach around .
... Future space-based gravitational wave detectors, such as the LISA-TianQin networks, will be capable of detecting alternative polarizations of stochastic backgrounds [91]. Moreover, utilizing noise-free correlation measurements from pulsar timing arrays will enhance our understanding of the nanohertz stochastic gravitational wave background, thereby providing deeper insights into gravity [92]. ...
Scalar-tensor gravity, exemplified by Brans-Dicke (BD) gravity, introduces additional scalar polarization modes that contribute scalar radiation alongside tensor modes. We conduct a comprehensive analysis of how gravitational wave generation and propagation effects under Brans-Dicke gravity are encoded into the astrophysical stochastic gravitational wave background (AGWB). We perform end-to-end analyses of realistic populations of simulated coalescing binary systems to generate AGWB mock data with third-generation gravitational wave detectors and conducted a complete Bayesian analysis for the first time. We find the uncertainties in the population properties of binary black holes (BBH) significantly affect the ability to constrain BD gravity. Under the most favorable conditions, the upper limit may suggest . Furthermore, we explore the detectability of potential scalar backgrounds arising from binary neutron star (BNS) mergers, setting upper limits on scalar backgrounds expected to be two orders of magnitude lower than the total background contributed by both BBH and BNS in one year of observational data. We conclude that for ambiguous populations, employing waveform matching with individual sources provides a more robust approach to constrain Brans-Dicke gravity. However, the future detection of a potential scalar background within the AGWB could provide significant support for gravity theories beyond General Relativity.
We investigate the sensitivity and performance of space-based optical lattice clocks (OLCs) in detecting gravitational waves, in particular the stochastic gravitational wave background (SGWB) at low frequencies (10−4, 1) Hz, which are inaccessible to ground-based detectors. We first analyze the response characteristics of a single OLC detector for SGWB detection and compare its sensitivity with that of laser interferometer space antenna (LISA). Due to longer arm lengths, space-based OLC detectors can exhibit unique frequency responses and enhance the capability to detect SGWB in the low-frequency range, but the sensitivity of a single OLC detector remains insufficient overall compared with LISA. Then, as a preliminary plan, we adopt a method of cross-correlation on two OLC detectors to improve the signal-to-noise ratio (SNR). This method leverages the uncorrelated origins but statistically similar properties of noise in two detectors while the SGWB signal is correlated between them, thus achieving effective noise suppression and sensitivity enhancement. Future advancements in OLC stability are expected to further enhance their detection performance. This work highlights the potential of OLC detectors as a promising platform for SGWB detection, offering complementary capabilities to LISA, and opening an observational window into more astrophysical sources and the early universe.
Scalar-tensor gravity, exemplified by Brans-Dicke (BD) gravity, introduces additional scalar polarization modes that contribute scalar radiation alongside tensor modes. We conduct a comprehensive analysis of how gravitational wave generation and propagation effects under Brans-Dicke gravity are encoded into the astrophysical stochastic gravitational wave background (AGWB). We perform end-to-end analyses of realistic populations of simulated coalescing binary systems to generate AGWB mock data with third-generation gravitational wave detectors and conducted a complete Bayesian analysis for the first time. We find the uncertainties in the population properties of binary black holes (BBH) significantly affect the ability to constrain BD gravity. Furthermore, we explore the detectability of potential scalar backgrounds that originates from binary neutron star (BNS) and neutron-star-black-hole (NSBH) mergers, with NSBH systems expected to modify the spectral index of the scalar background and introduce oscillatory behavior. We show that the observations of the AGWB enable the separation of mixed tensor and scalar polarization modes with comparable sensitivity to each mode. However, the scalar background is expected to remain substantially weaker than the tensor background, even in scenarios where BD gravity exhibits significant deviations from general relativity (GR), resulting only upper limits can be placed on the scalar background. We conclude that for ambiguous populations, employing waveform matching with individual sources provides a more robust approach to constrain BD gravity.
