17 January 2002

Quantum mechanics: Gravitational bound states

The gravitational force is very weak compared with electromagnetic and nuclear forces, so observation of an effect of Earth's gravitational field in the subatomic world of quantum mechanics is a considerable challenge. But that has now been achieved in an experiment using neutrons confined between a reflecting mirror on one side and Earth's gravitational potential on the other. Ultracold neutrons falling towards a horizontal mirror form gravitational quantum bound states. This is a further confirmation of the universality of the quantum properties of matter.

Quantum states of neutrons in the Earth's gravitational field
VALERY V. NESVIZHEVSKY, HANS G. B�RNER, ALEXANDER K. PETUKHOV, HARTMUT ABELE, STEFAN BAEßLER, FRANK J. RUEß, THILO ST�FERLE, ALEXANDER WESTPHAL, ALEXEI M. GAGARSKI, GUENNADY A. PETROV & ALEXANDER V. STRELKOV
Nature 415, 297–299 (17 January 2002)
| First Paragraph | Full Text | PDF (159 K) |

Quantum physics: Quantum effects of gravity
THOMAS J. BOWLES
The effects of gravity and quantum mechanics rarely overlap because of the different scales involved. An experiment with ultracold neutrons has now been able to probe both simultaneously.
Nature 415, 267–268 (17 January 2002)
| Full Text | PDF (110 K) |

Gravity leaps into quantum world