Mountain Trails of Quantum Phases
In a mountain range, there are trails that can be contracted to a point if you walk through a flat valley. But there are also loop routes that cannot be shrunk without crossing a ridge.
The Black Hole and Its Secret Twin
A rotating black hole is no calm whirlpool. Space around it shudders and rings at the slightest disturbance, like a guitar string after a pluck. These oscillations are described by the Teukolsky equation — a complex mathematical construct that physicists have studied for half a century.
Recently, a strange symmetry was noticed in this equation.
Shadow Theatre of Inflation: Quantum Masks of the de Sitter Vacuum
Inflation is the rapid expansion of the newborn Universe, when quantum fluctuations were stretched to cosmic scales. The cosmic microwave background is the fossilized light of that epoch, shadows on the wall of our cosmic cave.
When Time and Space Swap Roles: The Hidden Symmetry of the Quantum World
A translator gets distracted by every rustle in the hall, and a one-hour meeting stretches into two. That's roughly how ordinary quantum mechanics works: a particle evolves in time, while space serves as the stage. But what if we swapped their roles? Then the particle 'moves' through space, and time becomes a static backdrop.
Hidden Symmetry: How Particles Negotiate Their Own Rules
In particle physics, it has long been taken for granted that the forces of nature (electromagnetism, the weak and strong interactions) obey a strict symmetry called gauge symmetry. It's like a set of rules by which particles exchange force carriers. But where do the rules themselves come from?
Why Purple Bacteria Always Have Big Rings
In the depths of murky ponds, purple bacteria lurk. Their secret to surviving in near-total darkness is rings of light-catching molecules, arranged like a round dance: each dancer passes energy to a neighbor. But if the round dance has fewer than seven participants, the dance breaks down — energy scatters, and disorder takes over.
Symmetry rescues entanglement from thermal death
Quantum entanglement is a fragile resource. Heat a system, and thermal fluctuations will tear the delicate threads of correlations: at a sufficiently high but finite temperature, the Gibbs state of a local Hamiltonian becomes separable, that is, representable as a probabilistic mixture of products of local states.