Prospects of cosmic superstring detection through microlensing of extragalactic point-like sources

Abstract

The existence of cosmic superstrings may be probed by astronomical time domain surveys. When crossing the line of sight to point-like sources, strings produce a distinctive microlensing signature. We consider two avenues to hunt for a relic population of superstring loops: frequent monitoring of (1) stars in Andromeda, lensed by loops in the haloes of the Milky-Way and Andromeda and (2) supernovae at cosmological distances, lensed by loops in the intergalactic medium. We assess the potential of such experiments to detect and/or constrain strings with a range of tensions, 10 −15 Gµ/c 2 10 −6 . The practical sensitivity is tied to cadence of observations which we explore in detail. We forecast that high-cadence monitoring of ∼ 10 5 stars on the far side of Andromeda over a year-long period will detect microlensing events if Gµ/c 2 ∼ 10 −13 , while ∼ 10 6 stars will detect events if 10 −13.5 < Gµ/c 2 < 10 −11.5 ; the upper and lower bounds of the accessible tension range continue to expand as the number of stars rises. We also analyse the ability to reject models in the absence of fluctuations. While challenging, these studies are within reach of forthcoming timedomain surveys. Supernova observations can hypothetically constrain models with 10 −12 < Gµ/c 2 < 10 −6 without any optimization of the survey cadence. However, the event rate forecast suggests it will be difficult to reject models of interest. As a demonstration, we use observations from the Pantheon Type Ia supernova cosmology data-set to place modest constraints on the number density of cosmic superstrings in a poorly tested region of the parameter space.

Clustering of cosmic string loops

“…The loops could then be much closer to the Earth than they would otherwise be, and their observational effects, such as microlensing of stars [3,5,6] or gravitational waves [7,8], could be more pronounced. Since Chernoff's work of 2009, no independent analysis of loop clustering in galaxies has been performed.…”

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Clustering of cosmic string loops

“…(25). 6 The first term in Eq. ( 27) decreases with time, while the second (rocket) term grows with time.…”

“…We have verified that with this definition of t eq Eq. (25) gives an accurate transition from radiation to matter eras 6. Here we have assumed FRW cosmology, i.e.…”

Construction of Quantum Target Space from World-Sheet States using Quantum State Tomography

“…Motivated by this observation, we expect that in string theory, information obtained from world-sheet should be used to construct quantum states of target space. It may be noted that the that string correlation functions have been used to analyze the behavior of world-sheet string states [37,38,41,42]. Now as it is known that information about a quantum system can obtain from correlation functions [33,34,35,36], information theory has already been used to analyze the world-sheet string states.…”