I am a quantum space-time phenomenologist. I study the question of whether the space-time we live in is a definite reality that is a background on which all matter and light exist, or if it is an emergent phenomenon from a fundamentally indeterminate quantum system. Is the fabric of space-time absolute, or does it arise only as a specific observation made by a specific observer, with its true nature probabilistic and woven out of relationships among the building blocks of reality? I study this question from an empirical perspective, constructing models that attempt to describe actual experiments and observations, designing research programs to test those models, interpreting data to understand what it tells us about the underlying laws and principles, and sometimes even taking a role in the commissioning and operations of an experiment. Currently, I am carrying out the latest second-generation Holometer research program at Fermi National Laboratory, which measures tiny fluctuations of space-time at unprecedented precision (1/100,000,000 of a single atom!) to see if its background fabric is very subtly twisting due to quantum indeterminacies.
My research aims to address a number of fundamental mysteries. One is the holographic universe: Traditionally, it was widely thought that a breakdown of the familiar smooth space-time we experience happened only at the Planck scale, 10⁻⁴⁴ seconds. But we have since learned that black holes, the densest objects possible in general relativity, have information contents that are merely 2-dimensional. If we had a 3+1 dimensional background of space-time that is smooth all the way down to Planck scale resolution, even "empty" vacuum would hold a huge information content — at just the radius of Hawaii (Big Island), denser than a black hole! So the entire universe must somehow be a hologram with just 2 dimensions' worth of information, implying that the uncertainties in its background fabric are much larger. Another significant topic is "dark energy": The universe is expanding at an accelerating rate, with an unknown energy driving it. A common hypothesis is that this is the energy of empty space-time, but an estimate using standard physics would yield a value that is too large by 10¹²² — the worst failed calculation in physics. This anomalously "fine-tuned" small value is critical for the universe to come to its structured existence! We think that a reformulation using our models of quantum space-time may address the incorrect scaling. Lastly, I am interested in foundational problems in quantum mechanics: There have been many attempts to rigorously test whether quantum indeterminacies are fundamental features of reality, or merely reflections of our ignorance of the underlying total information available in the universe, but none of the mathematical models used to describe these experiments have included a quantum space-time as part of the physical system. While we are nowhere close to closing this loophole, an empirical verification of my models at the Holometer would take us a step closer.
A slightly more technical and involved description follows below.
Above : First-generation results, showing a strain spectral density of less than 0.1 Planck time.
Below (1) : Entanglement via causal structures, overlaid with the geometric path being foliated.
Below (2) : Schematic design for the reconfiguration to a bent-arm Michelson interferometer.