Gravitational waves from quasinormal modes of a class of Lorentzian wormholes

Abstract

Quasinormal modes of a two-parameter family of Lorentzian wormhole spacetimes, which arise as solutions in a specific scalar-tensor theory associated with braneworld gravity, are obtained using standard numerical methods. Being solutions in a scalar-tensor theory, these wormholes can exist with matter satisfying the Weak Energy Condition. If one posits that the end-state of stellar-mass binary black hole mergers, of the type observed in GW150914, can be these wormholes, then we show how their properties can be measured from their distinct signatures in the gravitational waves emitted by them as they settle down in the post-merger phase from an initially perturbed state. We propose that their scalar quasinormal modes correspond to the so-called breathing modes, which normally arise in gravitational wave solutions in scalar-tensor theories. We show how the frequency and damping time of these modes depend on the wormhole parameters, including its mass. We derive the mode solutions and use them to determine how one can measure those parameters when these wormholes are the endstate of binary black hole mergers. Specifically, we find that if a breathing mode is observed in LIGO-like detectors with design sensitivity, and has a maximum amplitude equal to that of the tensor mode that was observed of GW150914, then for a range of values of the wormhole parameters, we will be able to discern it from a black hole. If in future observations we are able to confirm the existence of such wormholes, we would, at one go, have some indirect evidence of a modified theory of gravity as well as extra spatial dimensions. * Electronic address: aneesh.

Wormholes with nonexotic matter in Born-Infeld gravity

“…See [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and references therein for some such examples. Also see [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] for some recent works on different aspects of wormholes.…”

Quasi-normal modes in a symmetric triangular barrier

“…For Ellis-Bronnikov geometry, the potential is symmetric about r * = 0 so the solutions can be divided into symmetric and anti-symmetric types. A similar treatment can be found in [11]. Hence the initial conditions for the two classes of QNMs will be: ψ(0) = 0 for antisymmetric solutions and ψ ′ (0) = 0 for symmetric solutions.…”

“…We will only consider the symmetric case which has smaller damping. We have followed the procedure for direct integration as given in [11]. The wave function is suitably expanded upto finite but arbitrary orders both near the throat and at spatial infinity.…”

“…and not on the cause producing them. This can help us in obtaining information about the parameters of a black hole or even a wormhole [11]. Through the nature of the solutions for the scalar or tensor QNMs, one can differentiate various theories of gravity [12].…”

Charged scalar quasi-normal modes for higher-dimensional Born–Infeld dilatonic black holes with Lifshitz scaling

“…These models have been generalized to Randall-Sundrum brane world models with warped extra dimensions, such that the effective Planck scale again reduce to a T eV scale [17,18]. It has been argued that such models motivated by string theory can be detected by analyzing the QNMs obtained from gravitational antennas [19][20][21][22]. However, as the effective Planck scale is brought down in these models, it is important to consider a UV completion of the effective theory in four dimensions for analyzing such black holes.…”