QUANTUM WEIRDNESS

                                  QUANTUM WEIRDNESS

Is quantum mechanics really as weird as it’s often made out to be? Here we take a brief look at three aspects of the subject. Although the conclusions reached may be known, or possibly in error, some may deserve greater consideration. We also briefly consider the double slit experiment.

(The words light and photons are used interchangeably as terms to cover the whole electromagnetic spectrum)

1. WAVE-PARTICLE DUALITY

Light is often described as having both wave and particle properties which for many purposes, are good descriptions. However, it should be better recognised that these properties are not exclusive to light. Unlike intrinsic properties such as the speed of light, which are independent of measurement, wave and particle descriptions depend on the interacting systems of which light is one part. In two-slit experiments the systems include the structure and geometry of the experimental arrangement used.

CONCLUSION Light is not exclusively a wave or a particle. Rather, there are situations for which it can be usefully modelled as having wave properties and others for which it can be usefully modelled as having particle properties.

• QUANTUM SUPERPOSITION

Popular descriptions of superposition describe things such as particles moving to the left while moving to the right, or the right way up while upside down.  Such descriptions appear nonsensical because they refer to situations that are mutually exclusive.

It can be more helpful to define quantum superposition with reference to probability and the Born rule, which can be used to calculate the probability of what is observed when a measurement is made.

CONCLUSION Quantum superposition is a state in which a measurement will reveal one of several possible outcomes, with probabilities predicted by the Born rule. In this sense, it is the probably amplitudes that are in superposition.

• UNSTABLE EQUILIBRIUM

A quantum superposition may be viewed as a state of unstable equilibrium between the possible outcomes that can be observed. This state may be so finely balanced that a slight disturbance, including an observation, tips it out of balance and into one of the outcomes.

Analogous examples from classical physics include:

• A radioactive particle close to decay.
• A pencil balanced on its point.
• An electrons and proton separated by infinity.

CONCLUSION Quantum superposition may be a state of unstableequilibrium between the possible outcomes that can be observed.

ONE PHOTON AT A TIME DOUBLE-SLIT EXPERIMENTS

In standard quantum mechanics it is assumed that each photon incident on a double slit somehow samples both slits simultaneously, the explanation usually referring to concepts such as probability waves. Here we explore a possible picture in which each photon, remaining entirely intact and undivided moves through both slits simultaneously while its integrity is maintained

THE MECHANISM

As the photon approaches the double slit, its effective shape adapts to the geometry of the openings. This allows the single photon to pass through both slits at the same time without dividing into separate parts. The photon remains one entity, but its extent spans the two slits.

After passing through the slits, the photon diffracts from each opening. These diffracted parts overlap and interfere with one another. This interference determines the probability of where the photon will be detected.

At no stage does the photon split into separate pieces. Its shape and location simply change as it passes through the apparatus. Detection still occurs as a single localised event.

In summary, the photon starts as one entity, passes through both slits by changing its effective shape, and is detected as one indivisible unit.