For nearly two hundred years, physics has lived by a sacred rule: no engine can ever be more efficient than the Carnot limit. This boundary, carved into the laws of thermodynamics by Sadi Carnot in 1824, has guided engineers and scientists alike, reminding us that there are hard ceilings on how much useful work can be extracted from heat. To challenge this principle was to question one of the bedrocks of modern science itself.
But in a daring twist, researchers have now designed a theoretical machine that seems to do the impossible. Dubbed the Gambling Carnot Engine (GCE), this nanoscale system reportedly reaches efficiencies of 100%—breaking the once inviolable Carnot limit—while also enhancing power generation. The revelation, published in Physical Review Letters, is shaking the intellectual foundations of thermodynamics, sparking both wonder and debate.
At the heart of the breakthrough lies a bold idea: that thermal fluctuations—the random jiggles of particles at the microscopic scale—can be strategically exploited, like a gambler who bets only when the odds are in their favor.
Curiosity at the Edge of Physics
Dr. Édgar Roldán, who led the research from the Abdus Salam International Center for Theoretical Physics, describes his fascination with engines as both deeply personal and universal. “I have always been fascinated by how engines work, from the engine of a car, or more sophisticated machines, both artificial, such as solar cells, or natural, such as cells and organisms,” he explained in an interview.
It is this mixture of wonder and rigor that animates the project. The team’s work belongs to a growing field known as stochastic thermodynamics, which studies how energy transforms at microscopic scales where randomness is not a nuisance but a resource. Here, heat does not flow smoothly as in a car engine—it fluctuates wildly, and with careful strategy, those fluctuations can be harnessed.
What Makes the Gambling Carnot Engine Different
Traditional heat engines, from steam locomotives to modern power plants, obey the Carnot efficiency formula:
η = 1 – (Tc/Th)
Here, Th is the temperature of the hot reservoir, and Tc is the cold reservoir. No matter how clever the design, no engine could ever exceed this mathematical bound—at least, not without violating the second law of thermodynamics.
The Gambling Carnot Engine rewrites the story by introducing an element of strategy. Inspired by game theory and borrowing language from casinos, the researchers describe their system as playing a “gambling game” with nature. Like a blackjack player who only risks betting when holding a strong hand, the GCE “bets” on certain favorable fluctuations in particle motion and refuses to play during less favorable ones.
This selectivity, enforced by a feedback controller—a kind of modern version of Maxwell’s famous “demon”—transforms chance into a tool.
How the Engine Works at the Microscopic Level
The GCE is not a piston or turbine. Instead, it is built from a colloidal particle, a tiny polystyrene bead suspended in water, confined by beams of focused light known as optical tweezers. On this miniature stage, energy cycles unfold not in roaring combustion chambers but in delicate shifts of laser intensity.
The cycle’s key step is the isothermal compression phase. Ordinarily, compressing the particle’s trap requires significant work. But in the GCE, a “demon” watches the particle’s position with extreme precision, using high-speed laser interferometry.
If the particle crosses the central point of the trap before a set deadline, the system instantly switches to its final compressed state—at zero work cost. In effect, the engine waits for the particle to “roll the dice” favorably before cashing in. Over many cycles, this selective timing generates an efficiency that approaches 100%.
Brownian Motion Becomes a Currency
The scientific brilliance of the design lies in how it exploits Brownian motion—the jittery, random movement of particles in fluid caused by collisions with surrounding molecules. In most cases, Brownian motion is noise. In the GCE, it is capital.
Each tiny fluctuation becomes an opportunity, and the engine’s gambling strategy determines whether to “invest” or wait. The mathematics reveals that as the timescales grow long—approaching the quasistatic limit—the efficiency rises toward perfection.
This is not just theory for its own sake. At nanoscale dimensions, fluctuations are not rare disturbances—they dominate the system. By turning randomness into a resource, the GCE offers a conceptual blueprint for energy harvesting in future nanoscale machines.
Does This Break the Laws of Physics?
The suggestion of beating Carnot efficiency naturally raises alarms. Thermodynamics, after all, is not known for exceptions. Dr. Roldán and his colleagues are careful to clarify: the GCE does not violate the second law. Instead, it expands the playing field by incorporating the role of information.
When efficiency is calculated in the traditional way—work extracted divided by heat intake—the GCE surpasses Carnot and even reaches unity. But when the energetic cost of acquiring and processing information is included—particularly the cost of erasing data about the particle’s position—then the complete picture respects classical thermodynamic limits.
This distinction is subtle but profound. It echoes a century of debate sparked by Maxwell’s demon, the thought experiment in which a tiny being could seemingly break the second law by sorting molecules. Physicists have since shown that information has energy costs, and the GCE is a modern incarnation of that principle.
From Theoretical Beauty to Experimental Reality
Skepticism is natural with such bold claims, but the researchers are confident their design can be realized experimentally. Their simulations use realistic parameters from earlier optical tweezer experiments, including their own demonstration of the first nanoscale Carnot engine with a polystyrene bead.
The challenges are significant. Monitoring particle position requires sampling rates above 100 kilohertz. Any slower, and the feedback lags too much to exploit fluctuations effectively. Implementing such ultrafast detection and control pushes experimental technology to its limits, but not beyond them.
If realized in practice, the Gambling Carnot Engine could serve as both a milestone in fundamental physics and a template for future nanotechnology, where devices must extract energy from noisy, fluctuating environments.
Why This Discovery Matters
At first glance, an abstract thermodynamic engine working on a microscopic bead might seem far removed from everyday life. But the implications ripple outward. Modern technology is moving relentlessly toward the nanoscale—molecular machines, biomedical devices, quantum information processors. In this frontier, classical engines are useless; we need designs that work with, not against, thermal noise.
The Gambling Carnot Engine does more than offer a new design. It redefines how we think about efficiency, power, and the role of information in physical processes. It tells us that the boundaries of thermodynamics are not brick walls but evolving landscapes, responsive to new insights into the nature of information and control.
It also reminds us of something more human: that progress often comes not from obeying old rules but from questioning them, even when those rules seem unbreakable.
A Gamble Worth Taking
As bold as its name, the Gambling Carnot Engine dares to play a game with one of physics’ oldest laws. Yet it does so without cheating, revealing instead that the game itself was more nuanced than we ever realized.
Carnot’s 19th-century insight built the foundation of thermodynamics, but Roldán and his team show that by weaving in the threads of information, feedback, and strategy, new paths emerge—paths that might one day power machines too small to see, yet powerful enough to change our world.
In science, the greatest discoveries often feel like gambles—risky, uncertain, even reckless. But as this new engine shows, sometimes the gamble pays off.
More information: Tarek Tohme et al, Gambling Carnot Engine, Physical Review Letters (2025). DOI: 10.1103/w8cx-xx1z
