A quantum number describes the energies of electrons in atoms. Each quantum number specifies the value of a conserved quantity in the dynamics of the quantum system. Since any quantum system can have ...

A gold superconducting quantum computer hangs against a black background. Quantum computers, like the one shown here, could someday allow chemists to solve problems that classical computers can’t.

Computing hasn’t changed fundamentally since the advent of the abacus 4,500 years ago. But that could change imminently as the world ushers in the quantum computer, a radically new type of computing ...