The prevailing assumption has been that Einstein's theory of gravity must be modified, or 'quantized', in order to fit within quantum theory. This is the approach of two leading candidates for a ...

In 1980, Stephen Hawking gave his first lecture as Lucasian Professor at the University of Cambridge. The lecture was called "Is the end in sight for theoretical physics?" Forty-five years later, ...

String theory offers a unified framework in which the fundamental constituents of nature are one-dimensional objects whose vibrational modes give rise to particles and forces. By embedding gravity ...

Modern physics theories highlight the key role of horizons—boundaries beyond which information cannot reach an observer—in a variety of cosmological and gravitational phenomena. Two renowned examples ...

Fifty-eight years after it first appeared, string theory remains the most popular candidate for the “theory of everything,” the unified mathematical framework for all matter and forces in the universe ...

The ball rolls across the floor because it was kicked, just as Earth orbits the sun because it is tugged by gravity. The connection between cause and effect is fundamental to how we understand the ...

String field theory is a second-quantised framework that recasts the perturbative dynamics of strings in terms of field-theoretic variables on the space of string configurations. By organising ...

The year 2025 marks the 100th anniversary of the birth of quantum mechanics. In the century since the field’s inception, scientists and engineers have used quantum mechanics to create technologies ...