# Quantum Gravity Research, But A 1000x Smaller | Ivette Fuentes Source: https://www.youtube.com/watch?v=0azYGnISuMY Recap page: https://rapidrecap.app/video/0azYGnISuMY Generated: 2025-12-26T20:03:28.235+00:00 --- ## Quick Overview Physicist Ivette Fuentes is pioneering research into quantum gravity using tabletop experiments involving Bose-Einstein condensates, aiming to test theories like the Diósi-Penrose collapse model by probing how massive systems behave in quantum superposition, which contrasts with conventional gravitational wave detection using large apparatus like LIGO. **Key Points:** - Fuentes compares her approach in physics to her first love, dance, viewing physics as a 'dance between the fields' that led her to break conventional career paths. - She is conducting groundbreaking work by proposing to detect gravitational waves using tabletop experiments based on Bose-Einstein condensates (BECs), an ultra-cold state of matter, contrasting with the 3 km arms of LIGO used for current detection methods. - Fuentes found a key incompatibility between quantum mechanics (using Galilean transformations where time is absolute) and general relativity (using Lorentz transformations where time is relative). - She was initially drawn to quantum mechanics and general relativity after abandoning classical physics, but later felt that mainstream approaches like string theory, with its many dimensions, were overly complicated, reminding her of Ptolemaic epicycles. - Her current research focuses on testing the Diósi-Penrose conjecture, which posits that gravity collapses the wave function for massive systems, unlike massless particles like photons which can be entangled over vast distances. - A Bose-Einstein condensate is an ultra-cold state where multiple boson atoms merge into a quantum state, becoming 'everywhere de-localized in the potential,' which Fuentes uses to study quantum gravity effects on these large, yet controllable, systems. - Fuentes is actively collaborating with experimentalists, such as Chris Foot at Oxford, to produce the necessary 'squeezed states' within large BECs to test these gravitational collapse theories, which she is refining beyond the initial models proposed by Diósi and Penrose. **Context:** The interview features physicist Ivette Fuentes, hosted by the Asencia Foundation, discussing her unconventional research path that blends quantum optics, general relativity, and experimental physics, often drawing parallels to her background in professional ballet. The conversation sets the stage by exploring the fundamental tension between quantum mechanics and general relativity and then delves into Fuentes's unique methodology of using Bose-Einstein condensates (BECs) to explore quantum gravity effects on macroscopic scales, which has attracted collaboration from figures like Roger Penrose. ## Detailed Analysis Ivette Fuentes describes her career as a 'dance' between different fields, leading her to groundbreaking work in quantum gravity research using small-scale tabletop experiments involving Bose-Einstein condensates (BECs), an ultra-cold quantum state where atoms become de-localized within a potential well. She highlights the fundamental incompatibility between quantum mechanics and general relativity stemming from their differing transformation laws (Galilean vs. Lorentz). Fuentes rejected the high-dimensional complexity of string theory, favoring experimental avenues that tested quantum foundations, eventually leading her to apply quantum optics tools to quantum field theory in curved spacetime, an intermediate step. Her current focus is testing gravitational collapse theories, specifically the Diósi-Penrose conjecture, which suggests gravity causes wave function collapse at a certain mass scale (estimated around 4 * 10^9 atoms). She is developing her own refinement of this conjecture, moving beyond the initial energy-time uncertainty principle models proposed by Penrose and the stochastic equation proposed by Diósi, whose model was partially ruled out by an experiment searching for predicted radiation. Fuentes's BEC approach offers a method to test these collapse models with massive systems at much smaller scales than traditional gravitational wave detectors like LIGO, proposing that the quantum waves (phonons) within the condensate are sensitive enough to detect spacetime perturbations like high-frequency gravitational waves. ### Personal and Professional Philosophy - Fuentes views physics as a 'dance,' requiring passion, similar to her former pursuit of classical dance - She fell in love with physics upon learning mathematics from first principles and later through quantum mechanics and general relativity. ### Quantum Gravity Conflict - The core incompatibility lies between Galilean transformations in QM (absolute time) and Lorentz transformations in GR (relative time) - Quantum Field Theory in Curved Spacetime is a semiclassical step where spacetime is classical (given by Einstein's equations) but fields are quantized, lacking back-reaction. ### Testing Collapse Theories - Fuentes explores the Diósi-Penrose conjecture, which predicts a limit where gravity collapses superposition, explaining why we don't see large superpositions - This contrasts with entanglement experiments on massless photons, which scale easily over long distances. ### Bose-Einstein Condensate Methodology - BECs are systems of bosons cooled to near zero temperature where atoms occupy the same ground state, forming 'quantum waves' called phonons - These phonons are proposed as highly sensitive quantum antennas to detect spacetime changes, potentially testing gravitational effects on a tabletop scale. ### Experimental Collaboration and Refinement - Fuentes works with experimentalists to produce necessary 'squeezed states' in large BECs to test collapse models - She is developing her own modification to the Diósi-Penrose conjecture, noting previous models (like Diósi's energy-non-conserving equation) faced experimental scrutiny.