This is a derivative from the wave-particle duality phenomenon.
After J. J. Thomson’s cathode-ray tube experiment, electrons were known for a long time to be particles. Louis De Broglie, however, predicted that electrons had a wave property in the 1920s. This was confirmed in an experiment where electrons showed interference in Young’s setup-like.
An electron is a wave with varying amplitudes in 3D space. This is the wave behaviour.
The Schrodinger equation quantifies this behavior. An election around a nucleus can be described as a standing wave and can only occupy orbits that are integral multiplies of its wavelength.
Now, according to the particle theory, the amplitude of the wave at any point in space can be interpreted as being proportional to its probability of being at the point at a given time, with the highest probability of its occurrence being at the center.
It would be incorrect to claim that the electron exists in multiple locations at once. Instead, the electron is present in all locations at once, and its amplitude decreases rapidly as you move away form the center of symmetry.
Human beings, or we, can be described as the sum of waves made up of particles. My velocity and position are known for most classical mechanics purposes. However, Heisenberg’s magnitude of error is insignificant. The probability that I exist at the end or on Mars is non-zero. All particles are waves, which means we exist everywhere in space, so you and me can also exist there. My case is that the sum of my particle wave probabilities are highest at Pittsburgh. They are located in the wave cloud near my laptop and interfere with everything around them.
Fascinating, isn’t it?