## Quantum Enigma part 4 (review)- “reality,” separability, and entanglement.

What Einstein once called “spooky actions” were proven to actually exist after Bell’s theorem demonstrated them in the laboratory. These “spooky actions” are now called entanglement, and this is when one object influences another without any physical force connecting the two.

Bell’s Theorem: suppose our world has physically real properties that are not created by their observation (this would be, ‘reality’). Also, suppose that objects can be separated from each other so that what happens to one cannot instantaneously affect the other (and the term that refers to this would be ‘separability’). Using only these to premises, Bell assumed that certain observable quantities could not be larger than certain other observable quantities. Now we have “Bell’s inequality” where this must be true in any world with reality and separability. If Bell’s inequality is violated in any situation, one or both premises logically leading to it (reality and separability) must be false. In other words, if Bell’s inequality is ever violated, no objects with reality and separability can exist in our actual world. Bell expected the inequality to be violated, as quantum theory predicts.

Intentionally ridiculous story to explain “twin-state” photons being polarized (experiment used to demonstrate the results of Bell’s Theorem)- Imagine that a photon is steered by a little “photon pilot” and the polarizer is just a traffic sign indicating an “orientation” with an arrow. The photon pilot carries a travel document instructing him how to steer his photon on path 1 or path 2 depending on the traffic sign. His sister, piloting the photon’s twin, follows her identical instructions at the traffic sign she encounters with no regard for the behavior of her brother.

When the experiments were done, Bell’s inequality was, in fact, violated. Our real world therefore, does not have both reality and separability. But what is reality?

John Clauser was intrigued by Bell’s theorem and quantum theory. He decided to test Bell’s inequality himself. His experiments showed that properties of our world either have only an observation-created reality, or, that there exists a connectedness beyond that diminished by ordinary physical forces, or both. “My own. . . vain hopes of overthrowing quantum mechanics were shattered by the data.” – John Clauser. Clauser’s experiment produced strong confirmation that Bell’s inequality was violated in the way quantum theory predicted.

So what does the violation of Bell’s inequality tell us?

“Reality”- term used for the existence of physically real properties not created by their observation.

Definition of physical reality in EPR: If a property of an object can be known without any observation of it, that property was not created by observation. It thus existed as a physical reality.

Quantum theory denies this “reality.” After experimentation, it is ruled out that we cannot have both reality and separability. The experiments rule out separability in our actual world.

Separability- the ability to separate objects so that what happens to one in no way affects what happens to others. Without separability, what happens at one place can instantaneously affect what happens far away- even though no physical force connects the objects. This is what Einstein referred to as “spooky action” but Bohr referred to it as an “influence.” Considering our actual world does not have separability, which has generally been accepted, “Any objects that have ever interacted are forever entangled, and therefore what happens to one influences the other.. and the behavior of everything entangled with it….. Quantum theory has this connectedness extending over the entire universe….In a sense, since everything has at least indirectly interacted, there is thus, in principle, a universal connectedness.”

Inductive reasoning- the assumption that because one thing is the way it is, all things alike must be the same. Inductive reasoning entered the box-pairs experiment when we assumed we could have chosen to do the experiment opposite to what was actually done (look in the box instead of interference pattern..). “The enigma arose because we assumed we could have chosen to do other than what we in fact did,” assuming we had free will and our choice was not predetermined by what was “actually” in each set of box pairs. Denial of free will goes beyond the notion that what we choose to do is determined by the electrochemistry of our brain. This denial would imply a completely deterministic and conspiratorial world in which our supposedly free choices are programmed to coincide with an external physical situation. Inductive reasoning assumes that what we chose to observe represents everything related, and that we could have chosen to look at the opposite. Induction and free will are closely related.

So it has been claimed that you are quantum mechanically entangled with anyone you have ever encountered, presumably more so for more intense encounters. This is a stretch vastly beyond anything demonstrable, therefore beyond anything meaningful. Complex entanglement essentially becomes no entanglement. “Since truly macroscopic objects are almost impossible to isolate, they rapidly become entangled with everything else in their environment. The effect of such complex entanglement generally becomes undetectable. Nevertheless, there is, in principle, a universal connectedness whose meaning we have yet to understand. We can indeed ‘see the world in a grain of sand.’ ”

Interpreting the quantum enigma– there are many interpretations. The book presents ten of them. We have already discussed the Copenhagen interpretation, but just to refresh our memories- observation essentially creates the physical reality of the microscopic world, but the “observer” can, for all practical purposes, be considered to be a macroscopic measuring device, a Geiger counter, for example. Also, since we supposedly never see the microscopic world directly, we can ignore it’s weirdness and ignore physics encounter with consciousness. It’s suggested that we create the reality of the microscopic world by looking at it. However, big things (that are made up of the microscopic objects) are impossible to completely isolate, therefore, they are always being “observed” and are real enough. So big things are the only thing that matters for all practical purposes. This interpretation allows physicists to ignore the philosophical aspects of quantum theory, and get back to the practicality.

Decoherence– The term “collapse” was used to describe the process of observation by which a superposition state wavefunction becomes an observed single reality. Instead of collapse, a physicist today might use the word “decoherence.” This term refers to the now, well studied process by which a wavefunction of a microscopic object interacts with the macroscopic environment to produce the result we actually observe.

Many Worlds– there is no “collapse.” This interpretation refers to the cosmological idea that there are parallel worlds in which the reality of one world may be the opposite reality in another. In one world, Shrodinger’s cat is alive, in another it is dead. With this interpretation, you are part of the universal wavefunction. With the box pairs- when looking into one of the boxes, you entangle with the atom’s superposition state. You go into a superposition state both of having seen the atom in the box you looked in and also of having seen that box empty. There are now two of you, one in each of two parallel worlds. The consciousness of each one of you is unaware of the other “you.” Bell’s theorem suggests that our actual world cannot have reality and certainly cannot have separability (the ability to separate objects so that what happens to one in no way affects what happens to others. Without separability, what happens at one place can instantaneously affect what happens far away- even though no physical force connects the objects). In the Many Worlds interpretation there is no separability.  “Not only are we removed from the center of the cosmos to a tiny spot in a limitless universe, but the world we experience is just a minute fraction of all worlds. However, “we” exist in many of them. Many Worlds, the most bizarre description of reality ever seriously proposed provides a fascinating base for speculation, and for science fiction.”

Transactional– allows the wavefunction to evolve backward, as well as forward in time. In other words, the future affects the past. “When we stand in the dark and look at a star a hundred light years away, not only have the retarded light waves from the stars been traveling for a hundred years to reach our eyes, but the advanced waves generated by absorption processes within our eyes have reached a hundred years into the past, completing the transaction that permitted the star to shine in our direction” – John Cramer.

I have presented a handful of the interpretations that are in the book. Quantum mechanics shows that our reasonable, everyday worldview is fundamentally flawed. Interpretations of the theory offer different worldviews, but every one of them involves the mystery of consciousness. No interpretation can ever avoid the encounter with consciousness because the encounter arises directly from theory-neutral experimental demonstration. They can only offer a way to avoid dealing with consciousness.

We have learned that an object far away can influence the behavior of another without any physical force connecting the two, and our conscious perception of free will is hindered by this result. Was it our choice to observe the outcome of a particular experiment, or was our ‘choice’ predetermined by an influence beyond our knowing? Keep in mind, our perception of free will arises only from our conscious experience of it as being free. We know that we have free will because we experience it everyday. We believe we are conscious human beings because of our awareness of our surroundings and our subjective, inner experiences. I can be certain that I am a conscious individual because of my own internal experience. I cannot be certain, however, that my peers are nothing more than highly intelligent robots. We will next be looking into the mystery of consciousness, it’s encounter with the enigma, and conclude with what it all might mean.