One of the biggest unsolved problems in physics centers on a number known as the cosmological constant. This value describes the energy responsible for the universe's accelerating expansion. It also sits at the heart of a major conflict between two of science's most successful theories.
According to quantum field theory (QFT), the framework that describes elementary particles and their interactions, empty space should be filled with quantum fluctuations that contribute an enormous amount of energy. In fact, calculations suggest the cosmological constant should be extraordinarily large, effectively approaching infinity.
Yet observations show something very different. The actual value of the cosmological constant is incredibly small compared with what theory predicts.
Now, researchers at Brown University have proposed a possible explanation.
Their work suggests that a mathematical feature of space-time itself may prevent the cosmological constant from ballooning to the huge values expected from quantum physics. The idea draws on an unexpected connection between quantum gravity and the quantum Hall effect, a remarkable phenomenon in condensed matter physics.
