Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

## Friday, September 28, 2012

### Quantum entanglement, and the path of mental laziness

There are, as far as I can see, two reasons why people believe the counterfactual, unsubstantiated nonsense that I deride daily as "woo-woo."  One of them I can actually sympathize with; and that's "wishful thinking."  I know what it feels like to wish, vehemently, that the universe was other than it is.  And some of the things woo-woos would like to be true are admittedly pretty cool.  Wouldn't it be awesome if crystals could heal you of incurable diseases?  If you could find out why your love life is in a tailspin by looking at patterns of Tarot cards?  If there really was a reason for everything that happened, and that all of the apparent chaos of life was linked by some grand, cosmic plan?

The second reason for woo-woo beliefs, however, is one for which I have no sympathy whatsoever, and that's "laziness."  Practitioners of woo-woo often end up there because they are too mentally indolent to be bothered to learn the basics of scientific induction, or, in fact, any science at all.  Once you start delving into scientific explanations, and learning how to construct a rational argument, most woo-woo beliefs simply fall apart at the seams.  But science is hard; and the crystals-and-Tarot-cards set, it seems, would prefer the easy road of doing no real work to earn their understanding of the universe.

I ran into a spectacular example of this from our pal, frequent Skeptophilia flyer Diane Tessman, just yesterday.  Tessman, you might recall, is the one who believes that clouds are created by UFOs as camouflage, that the Higgs boson was predicted in Mayan prophecy and is responsible for consciousness, and that there is a superintelligent alien being called "the God Cloud" that is going to usher in a New Age of Enlightenment really soon.  So anything that Tessman has to say is bound to be worth reading, wouldn't you think?

Thus my excitement when I saw yesterday that she'd weighed in on the subject of Quantum Entanglement.  Here's a bit of what she had to say:
Quantum entanglement, which we humans are just now beginning to comprehend to some small degree, may explain many of the deepest, most sacred secrets of the cosmos, and open vistas to us of which we could only dream, before.

The first thing to realize: Quantum entanglement, although it sounds like one has been enveloped in an evil alien butterfly net, can be and often is – a good thing...

The second thing to realize: I believe there is general quantum entanglement and specific quantum entanglement; the latter is the kind of entanglement which aliens might use to reach individuals.

General quantum entanglement: We can look at love – particularly unconditional love – as the most powerful and ubiquitous form of general quantum entanglement. You love your daughter, unconditionally. You “get a feeling” when she does not come home on time after a date, that something is wrong. You have been involved with this other soul since her birth. Is it just genetics? No, it is all the crazy memories, all the times you protected her, all the special moments; you have become entangled with this other mind (this other being), beyond any undoing...  I believe there is a morphic (quantum) field which winds between two people like an electric spider web.

I feel quantum entanglement is one of the basic methods by which the universe electrically conveys evolution. Intelligence travels on the electromagnetic webbing, it travels in the quantum field of particles, waves, and strings.
It all sounds pretty... nice, doesn't it?  We're all connected, and a Quantumly Entangled Field conveys to us all such things as love and caring and special moments and warm fuzzies.  The Sacred Secrets Of The Cosmos are available to everyone because we're linked through a mysterious Electromagnetic Webbing.  Everything is all New-Agey and cosmic and dreamy.

But the problem is, is that really what physicists mean by the term quantum entanglement?  Well, let's do some actual work and find out.  First stop, the Wikipedia article on the phenomenon:
Quantum entanglement occurs when particles such as photons, electrons, molecules as large as buckyballs, and even small diamonds interact physically and then become separated; the type of interaction is such that each resulting member of a pair is properly described by the same quantum mechanical description (state), which is indefinite in terms of important factors such as position, momentum, spin, polarization, etc. According to the Copenhagen interpretation of quantum mechanics, their shared state is indefinite until measured.  Quantum entanglement is a form of quantum superposition. When a measurement is made and it causes one member of such a pair to take on a definite value (e.g., clockwise spin), the other member of this entangled pair will at any subsequent time be found to have taken the appropriately correlated value (e.g., counterclockwise spin). Thus, there is a correlation between the results of measurements performed on entangled pairs, and this correlation is observed even though the entangled pair may have been separated by arbitrarily large distances.
Quantum mechanical framework:  Consider two noninteracting systems $A$ and $B$, with respective Hilbert spaces $H_A$ and $H_B$. The Hilbert space of the composite system is the tensor product
$H_A \otimes H_B .$
If the first system is in state $\scriptstyle| \psi \rangle_A$ and the second in state $\scriptstyle| \phi \rangle_B$, the state of the composite system is
$|\psi\rangle_A \otimes |\phi\rangle_B.$
States of the composite system which can be represented in this form are called separable states, or (in the simplest case) product states.
Not all states are separable states (and thus product states). Fix a basis $\scriptstyle \{|i \rangle_A\}$ for $H_A$ and a basis $\scriptstyle \{|j \rangle_B\}$ for $H_B$. The most general state in $\scriptstyle H_A \otimes H_B$ is of the form
$|\psi\rangle_{AB} = \sum_{i,j} c_{ij} |i\rangle_A \otimes |j\rangle_B$.
This state is separable if $\scriptstyle c_{ij}= c^A_ic^B_j,$ yielding $\scriptstyle |\psi\rangle_A = \sum_{i} c^A_{i} |i\rangle_A$ and $\scriptstyle |\phi\rangle_B = \sum_{j} c^B_{j} |j\rangle_B.$ It is inseparable if $\scriptstyle c_{ij} \neq c^A_ic^B_j.$ If a state is inseparable, it is called an entangled state.
For example, given two basis vectors $\scriptstyle \{|0\rangle_A, |1\rangle_A\}$ of $H_A$ and two basis vectors $\scriptstyle \{|0\rangle_B, |1\rangle_B\}$ of $H_B$, the following is an entangled state:
${1 \over \sqrt{2}} \bigg( |0\rangle_A \otimes |1\rangle_B - |1\rangle_A \otimes |0\rangle_B \bigg)$.
If the composite system is in this state, it is impossible to attribute to either system $A$ or system $B$ a definite pure state. Another way to say this is that while the von Neumann entropy of the whole state is zero (as it is for any pure state), the entropy of the subsystems is greater than zero. In this sense, the systems are "entangled". This has specific empirical ramifications for interferometry.  It is worthwhile to note that the above example is one of four Bell states, which are (maximally) entangled pure states (pure states of the $H_A \otimes H_B$ space, but which cannot be separated into pure states of each $H_A$ and $H_B$).
Now suppose Alice is an observer for system $A$, and Bob is an observer for system $B$. If in the entangled state given above Alice makes a measurement in the $\scriptstyle \{|0\rangle, |1\rangle\}$ eigenbasis of A, there are two possible outcomes, occurring with equal probability:
1. Alice measures 0, and the state of the system collapses to $\scriptstyle |0\rangle_A |1\rangle_B$.
2. Alice measures 1, and the state of the system collapses to $\scriptstyle |1\rangle_A |0\rangle_B$.
If the former occurs, then any subsequent measurement performed by Bob, in the same basis, will always return 1. If the latter occurs, (Alice measures 1) then Bob's measurement will return 0 with certainty. Thus, system B has been altered by Alice performing a local measurement on system A. This remains true even if the systems A and B are spatially separated. This is the foundation of the EPR paradox.
The outcome of Alice's measurement is random. Alice cannot decide which state to collapse the composite system into, and therefore cannot transmit information to Bob by acting on her system. Causality is thus preserved, in this particular scheme. For the general argument, see no-communication theorem.
Had enough yet?  I certainly sympathize if you have.  This stuff is difficult.  I was a physics major, fer cryin' in the sink, and I have a hard time with this subject; the math is frankly beyond me, and just the concepts are tough to wrap your brains around even if you've read your share of Brian Greene and Stephen Hawking.  I get that.  To learn what the scientists are talking about requires some serious effort.

But at least try, for heaven's sake.  Find out a little bit of what the physicists actually mean by the word "quantum" before you start using it.  Read a couple of good books (by actual working physicists) on the subject.  At least do a damn Google search.  With sources like Wikipedia available to everyone who has a computer, there is no excuse whatsoever for the kind of mental laziness that the woo-woos seem to embrace.

The universe is weird, wonderful, mysterious, and beautiful.  But it is also complex, deep, and requires effort to comprehend.  Falling for Diane Tessman's "electromagnetic web of love and quantum consciousness" is taking the easy way out, accepting a wrong answer regarding how the universe works just because (1) it sounds nice, and (2) it takes less mental work.  Take the time to learn a little actual science; learn how the actual scientists do what they do.  You'll be amazed at how quickly whole worlds of new and astonishing knowledge will open up for you.  And even if you have to give up the comforting children's stories of Quantum Spiritual Energies Linked By Love And Light, you'll have gained insight into the actual workings of the cosmos.

And I consider that to be a fair trade.

1. "The first thing to realize: Quantum entanglement, although it sounds like one has been enveloped in an evil alien butterfly net, can be and often is – a good thing..."

It isn't good or bad, you dolt. The laws of physics do not carry an emotional component.
IT JUST IS.

The word quantum is used so it must be about "Aliens and the cosmos!" (Phasers on stun, danger Will Robinson, danger! Warp 9! The force is with you!)

While there a number of quanta that I could use to illustrate my point... to be succinct, Tessman has, quantifiably, some serious entanglement in her grey matter.

To the woo-woo sympathizers: It isn't "harmless."
It's incorrect and counter-productive. That's "harmful."

To be even more patronizing:
Being right is good.
Diane Tessman is wrong. That's bad.

How about. A $5 dollar bill and a$10 bill are in an envelope. Without looking, we take the bills out and put each one in a separate envelope. We post one to new york and the other to LA. in LA we open the envelope and it has a $10 bill in it. Instantaneously we know the envelope in New york has a$5 bill in it!? Magic or what? Surely the entanglement is just saying something logical not mysterious?