Thermodynamics rebuilt on gauge theory math
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- Bryan Roberts at the London School of Economics and Political Science is rebuilding thermodynamics using mathematical ideas drawn from geometry and quantum field theory, a notable departure from how the theory has long been understood and taught.
- Roberts's approach centers on gauge theory, which deals with properties that aren't directly observable, mapping thermodynamics onto a two-space structure where 'work' lives in an observable space and the hidden 'heat' component of energy is placed in a 'bundle' space.
- In traditional thermodynamics, work and heat are placed on equal footing and their sum accounts for changes in total energy, but Roberts argues heat's hiddenness justifies treating it differently and locating it in the unobservable bundle space.
- Temperature and entropy can be defined as a specific projection from the bundle space onto the observable space, yielding a more geometrical definition that Roberts says is easier to apply to general systems ranging from engines to black holes.
- Roberts anticipates preliminary experiments with certain molecular junctions hint at a thermodynamic version of the Aharonov-Bohm effect, where a charged particle appears to experience a hidden magnetic field.
- Roberts presented the work at the Foundations of Physics conference in Irvine, California, on 16 June.
- Lucas Céleri at the Federal University of Goiás in Brazil called the idea beautiful and complementary to his own group's efforts to formulate quantum thermodynamics as a gauge theory, noting the field currently suffers from too many competing definitions of heat and work.
Why it matters: If Roberts's gauge-theory framework holds up, it gives thermodynamics a rigorous mathematical backbone it has lacked for two centuries, letting physicists import proven gauge-theory results and potentially unifying classical and quantum thermodynamics — useful for everything from engine design to black-hole physics. Independent groups in Brazil are already reproducing standard quantum thermodynamic results through the same lens, suggesting the approach is gaining traction.
