Professor Anupam Mazumdar and the Search for Quantum Gravity in the Lab
September 14, 2026
By Lyuba Encheva, CITA
When Anupam Mazumdar first arrived in Canada in 2002, he was a CITA National Fellow stationed at McGill University, working at the frontier where particle physics meets the early universe. More than two decades later, he is returning to the Canadian Institute for Theoretical Astrophysics (CITA) at the University of Toronto as a full professor. In the intervening years, Prof. Mazumdar has developed one of the most distinctive research programs in theoretical physics: an attempt to catch gravity itself behaving like a quantum object, not out in space, but on a tabletop.
From the early universe to the quantum nature of spacetime
Mazumdar’s career has taken him through a remarkable circuit of the world’s leading theoretical physics institutes — Imperial College London, the International Centre for Theoretical Physics in Trieste, McGill, NORDITA and Niels Bohr Institute in Copenhagen, Lancaster University, and most recently the Van Swinderen Institute at the University of Groningen. Along the way, he built a reputation across several distinct areas of theoretical physics. These include cosmic inflation and the physics of the very early universe’s phase transitions. Prof. Mazumdar is also known for his “infinite derivative” theories of gravity — modified versions of general relativity designed to avoid the singularities — such as those at the centres of black holes — that plague Einstein’s original theory.
But it is a more recent line of work that has come to define his research identity. In 2017, Mazumdar and collaborators proposed an experimental protocol to test, in a laboratory, whether gravity is fundamentally quantum in nature. The idea, known as the Quantum Gravity Induced Entanglement of Masses (QGEM) protocol, asks a deceptively simple question: if you place two small masses side by side in quantum superpositions and let them interact only through their mutual gravitational pull, will gravity be able to entangle them the way quantum particles routinely entangle through electromagnetic or other known Standard Model forces? If it can, that would be direct evidence that gravity carries information the way quantum fields do — a long-sought clue in the decades-long effort to reconcile general relativity with quantum mechanics.
It is an audacious idea precisely because gravity is so weak. Unlike collider physics, which pushes to ever-higher energies to probe fundamental interactions, Mazumdar’s approach pushes toward ever more delicate, ever more isolated quantum systems — nanocrystals cooled and levitated with enough precision that gravity’s faint pull between them might, just barely, leave a detectable quantum fingerprint. In 2022, he extended the idea further, proposing a quantum-optics analog of the classic light-bending test of general relativity. This time the intention was to test whether the exchange of a single graviton could entangle photons and matter in quantum superposition.
The envisioned hardware for the flagship QGEM experiment is as exotic as the physics it is meant to probe: nanodiamonds (10 picogram mass), embedded with nitrogen-vacancy centres — atomic-scale defects that act as controllable quantum spins — levitated above a current-carrying superconducting chip and cooled toward the quantum regime in both their internal and centre-of-mass motion. A Stern-Gerlach-type protocol would use the embedded spin to split each nanodiamond into a spatial superposition, hold it open for roughly a tenth of a second to a full second, and then look for the telltale entangling phase that only a genuinely quantum gravitational interaction could imprint. The central experimental headache is separating that faint gravitational signal from electromagnetic backgrounds, since electromagnetic effects can be shielded away but gravity cannot — turning the experiment into what amounts to a very carefully controlled game of hide-and-seek with nature.
This is not a solo effort. Prof. Mazumdar is a co-principal investigator of the MAST-QG collaboration, which brings together University College London, Yale, Northwestern, and Warwick, and the QGEM program has drawn support from major philanthropic science funders, including the Gordon and Betty Moore Foundation and the Alfred P. Sloan Foundation. It is, in other words, an internationally resourced, multi-institution bet on a genuinely novel way of probing fundamental physics — and one that a research group at CITA now has a direct stake in.
Why CITA
CITA has long been a home for physicists who treat gravity and cosmology as an integrated whole — the origin of cosmic structure, the physics of the very early universe, gravitational waves, black holes and compact objects. Mazumdar’s work extends that tradition into a domain the Institute has not historically had in-house: table-top, laboratory tests of gravity’s quantum character. Rather than looking to the cosmos for evidence of quantum gravity’s effects, he is trying to manufacture the conditions for it in a lab on Earth — an approach that is complementary to, rather than in competition with, CITA’s traditional strengths in astrophysical gravity and cosmology.
There is also a symmetry to the appointment that is hard to overlook. Mazumdar’s first taste of Canadian science came as a CITA Fellow at McGill more than twenty years ago, at a formative stage in his career when he was still establishing himself in cosmology and particle physics. His return to CITA itself, now as a senior faculty member leading an internationally recognized experimental-theory program, closes a loop that began at the very outset of his career — and brings with it not just his own research group, but an entry point for CITA into the fast-moving, interdisciplinary field of quantum information science as it intersects with gravity.
With roughly 240 published papers, three major review articles in journals including Physics Reports and Reports on Progress in Physics, a multi-institution collaboration in MAST-QG, and philanthropic funding already secured from the Moore and Sloan foundations, Mazumdar arrives at CITA with both a substantial body of foundational work behind him and an ongoing, high-profile experimental program still very much in motion. For an institute built on the premise that some of the deepest questions in physics — the origin and fate of the universe, the nature of black holes, the unification of gravity and quantum mechanics — require sustained, focused theoretical effort, his presence adds a genuinely new avenue toward one of the oldest open problems in physics: whether gravity, like everything else we know, is quantum after all.
