[Paper Review] Astrometric detection feasibility of gravitational effects of quantum vacuum

M. Gai, Alberto Vecchiato|arXiv (Cornell University)|Jun 13, 2014

Cosmology and Gravitation Theories7 references4 citations

TL;DR

This paper investigates the feasibility of detecting gravitational effects from the quantum vacuum via astrometric measurements of the trans-Neptunian binary system UX25. It finds that with adaptive optics telescopes, a 3σ detection of an excess pericenter shift of ~0.23 arcsec/orbit—predicted by quantum vacuum gravity models—could be achieved in under two weeks of observation time over a few-year baseline.

ABSTRACT

This work analyzes in some detail the feasibility of testing with astrometric measurements the hypothesis that Quantum Vacuum can have gravitational effects, as suggested in a series of recent papers ([3, 6, 5]). In particular, the possibility of detecting an excess shift of the longitude of the pericenter in the orbit of the trans-neptunian system UX25 and its satellite is investigated. The excess shift which might be experimented by the orbit of the satellite was estimated, under reasonable working hypothesis, to be about 0:23 arcsec per orbit. Several observing scenarios are explored here, including those using conventional and adaptive optics telescopes from ground, and some spaceborne telescopes.

Motivation & Objective

• To assess whether astrometric measurements can detect gravitational effects attributed to the quantum vacuum, as proposed in recent theoretical work.
• To evaluate the feasibility of detecting an excess pericenter shift in the orbit of the trans-Neptunian binary system UX25.
• To compare the performance of adaptive optics (AO) and conventional ground-based telescopes for this detection task.
• To estimate required observation time and signal-to-noise ratio for a 3σ detection of quantum vacuum-induced precession.
• To determine whether current or near-future instrumentation can achieve unambiguous detection within a practical observational timescale.

Proposed method

• Model the expected quantum vacuum-induced pericenter shift in the UX25 binary system as ~0.23 arcsec per orbit under reasonable physical assumptions.
• Simulate astrometric observations using least-squares estimation of orbital precession over a 5-year baseline (~50 arcsec total precession).
• Assess performance for two telescope types: AO-equipped (resolving individual components) and conventional (measuring only photocenter motion).
• Estimate required observation time using signal-to-noise ratio (SNR) extrapolation, assuming K-band operation and 8m aperture telescopes.
• Account for instrumental limitations such as angular resolution, photon budget, and degradation at shorter wavelengths.
• Use a laser guide star system to enable AO operation, as the target lacks a sufficiently bright natural guide star.

Experimental results

Research questions

• RQ1 Can astrometric measurements detect an excess pericenter shift of ~0.23 arcsec/orbit induced by quantum vacuum gravity in the UX25 binary system?
• RQ2 What is the required observation time and signal-to-noise ratio for a 3σ detection using current ground-based telescopes?
• RQ3 How do the performance and feasibility differ between adaptive optics and conventional imaging telescopes for this measurement?
• RQ4 Is the Hubble Space Telescope a viable alternative, given its exposure time requirements?
• RQ5 Can service-mode observations with partial nights be used effectively to accumulate the necessary data over a few months?

Key findings

• The quantum vacuum-induced pericenter shift in the UX25 system is estimated at ~0.23 arcsec per orbit, a value potentially detectable via long-term astrometry.
• An 8m telescope with adaptive optics and a laser guide star can achieve a 3σ detection in less than two weeks of total observation time, primarily in the K band.
• Conventional ground-based telescopes are deemed impractical due to the need for extremely low astrometric noise to resolve the smaller photocenter motion.
• Hubble Space Telescope could in principle achieve the goal, but the required exposure time raises serious concerns about practical feasibility.
• The detection is feasible over a few years by cumulatively measuring the precession effect, with sparse coverage over several orbital periods being sufficient.
• Service-mode observations using underutilized time on AO telescopes could be a viable strategy for achieving the required data accumulation.