Quantum mechanics is the branch of physics that studies the behavior of matter and energy in the presence of an observer. It is the foundation of modern physics and the theory of the wave-particle duality.

In quantum mechanics, particles (like atoms and photons)ooze and change their states as they come into and leave contact with other particles. The behavior of a particularly stable subatomic particle, called a qubit, is described by a continuous Schr¨dinger equation in which the position, momentum, and energy of each qubit are jointly indeterminate.

In the Copenhagen interpretation of quantum mechanics, an observer is necessary to collapse the wave function and determine the outcome of an observation. This act of measurement disturbs the system being observed. The Heisenberg uncertainty principle states that certain properties of particles (such as position and momentum) cannot be known simultaneously with absolute certainty.

Quantum mechanics was developed in the early 1900s by a number of physicists, including Max Planck, Niels Bohr, Werner Heisenberg, and Erwin Schr¨dinger. These physicists were trying to understand the behavior of matter and energy on a subatomic level.

Today, quantum mechanics is used to describe the behavior of matter and energy in a wide variety of fields, including atomic and nuclear physics, condensed matter physics, quantum optics, and quantum information science.

## Other related questions:

### Q: Who established the foundations of the quantum theory?

A: The foundations of quantum theory were established by a number of physicists in the early 1900s, including Max Planck, Albert Einstein, Niels Bohr, and Erwin Schrödinger.

### Q: Who introduced the concept of quantum?

A: Quantum mechanics was developed in the early 1900s by a number of physicists, including Max Planck, Albert Einstein, Niels Bohr, and Erwin Schrödinger.

### Q: Who discovered quantum wave mechanics?

A: Quantum wave mechanics was discovered by Austrian physicist Erwin Schrödinger in 1925.