Measurement of Gravity and Gauge Fields using Quantum Mechanical Probes

Vivishek Sudhir

Gao, Shan

Testing whether gravity is quantum or classical remains a cornerstone challenge in fundamental physics. We introduce a practical tabletop experiment to probe gravity's quantum nature via the gravitational Aharonov-Bohm (AB) effect in atom interferometry. Our approach hinges on two pivotal insights: First, unlike electromagnetic AB effects where constant charge ensures gauge-invariant phases for closed paths, semiclassical gravity couples to the particle's total energy, rendering the AB phase gauge-dependent and unobservable when energies differ between paths due to environmental noise or controlled perturbations. Second, in quantum gravity—treating source, particle, and field as quantum—the total phase splits into a gauge-dependent particle contribution and a gauge-invariant source backreaction, yielding precisely half the nominal AB phase as observable. This halved phase discriminates quantum from classical gravity without requiring massive superpositions, aligning with existing technology. Remarkably, Overstreet et al.'s (Science 375, 226 (2022)) data already reveal a nonzero measured AB phase, providing the first experimental evidence for gravitational quantization.

Arttu Pönni

This thesis consists of four research papers and an introduction covering the most important concepts appearing in the papers. The papers deal with applications of gauge/gravity dualities in the study of various physical quantities and systems. Gauge/gravity dualities are equivalences between certain quantum field theories and classical theories of gravity. These dualities can be used as computational tools in a wide range of applications across different fields of physics, and as such they have garnered much attention in the last two decades. The great promise of these new tools is the ability to tackle difficult problems in strongly interacting quantum field theories by translating them to problems in classical gravity, where progress is much easier to make. Quantum information theory studies the information contained in quantum systems. Entanglement is the fundamental property of quantum mechanics that sets it apart from classical theories of physics. Entanglement is commonly quantified by entanglement entropy, a quantity which is difficult to compute in interacting quantum field theories. Gauge/gravity dualities provide a practical way for computing the entanglement entropy via the Ryu-Takayanagi formula. The primary focus of this thesis is to use this formula for computing various entanglement measures in strongly interacting quantum field theories via their gravity duals. The purpose of this thesis is to introduce quantum information theory concepts that have been important in our research. When applicable, quantities of interest are first introduced in the classical setting in order to build intuition about their behaviour. Quantum properties of entanglement measures are discussed in detail, along with their holographic counterparts, and remarks are made concerning their applications.

Fernando Sansò, Federica Migliaccio

kaifa chen

This paper presents a complete derivation chain: starting from the structure–symbol sample space (p,τ,P(τ∣p))(p,τ,P(τ∣p)) and the local irreversibility ΔSΔS, without introducing any additional quantum assumptions, it progressively derives the entire core structure of quantum mechanics, and further derives quantum field theory, gauge fields, gravity, and mass generation mechanisms. The core of the derivation chain is the natural linear structure of the Fisher metric in amplitude coordinates, and the topological properties of the Berry curvature on the logical manifold. This paper does not seek to "interpret" quantum mechanics, but to demonstrate that quantum mechanics can emerge from logical systems. The paper also lists both the core problems that have been solved and the open problems that remain, enabling readers to assess the boundaries of this path. Keywords: ΔS framework; Fisher metric; Berry curvature; Quantum emergence; Gauge fields; Gravity; Mass generation; Logical systems

Lajos Diósi