How Quantum Mechanics Could Be Even Weirder

Rather, the classical world emerges from the quantum in a comprehensible way: you might say that classical physics is simply what quantum physics looks like at the human scale.

.. Erwin Schrödinger, who invented the quantum wave function, discerned at once that what later became known as nonlocality is the central feature of quantum mechanics, the thing that makes it so different from classical physics.

.. Arguably it’s better to forget this picture of cause-and-effect: you could say that two entangled particles aren’t really two particles at all, but have actually become one single, nonlocalized quantum entity.

.. Given their super-efficiency, PR boxes could do computation even faster than quantum computers. Could they ever exist, though? Sure, the world looks quantum-mechanical, not super-quantum; but it also looked classical for a long time, until we figured out how to spot quantum nonlocality.

.. The question becomes not so much why nature isn’t completely classical, but why it’s not “more” quantum.

.. All this fits with a growing conviction among many physicists that quantum mechanics is at root a theory not of tiny particles, but of information.

How Many Decimals of Pi Do We Really Need?

Earlier this week, we received this question from a fan on Facebook who wondered how many decimals of the mathematical constant pi (π) NASA-JPL scientists and engineers use when making calculations:

.. by cutting pi off at the 15th decimal point, we would calculate a circumference for that circle that is very slightly off. It turns out that our calculated circumference of the 25 billion mile diameter circle would be wrong by 1.5 inches.

.. We can bring this down to home with our planet Earth. It is 7,926 miles in diameter at the equator. The circumference then is 24,900 miles. That’s how far you would travel if you circumnavigated the globe (and didn’t worry about hills, valleys, obstacles like buildings, rest stops, waves on the ocean, etc.). How far off would your odometer be if you used the limited version of pi above? It would be off by the size of a molecule.

.. How many digits of pi would we need to calculate the circumference of a circle with a radius of 46 billion light years to an accuracy equal to the diameter of a hydrogen atom (the simplest atom)? The answer is that you would need 39 or 40 decimal places.

Are the Constants of Physics Constant?

So far, they seem to be—but nobody really understands why

.. Born was after a unifying theory to relate all the fundamental forces of nature. He also wanted a theory that would explain where these constants came from. Something, he said, to “explain the existence of the heavy, and light elementary particles and their definite mass quotient 1840.”
.. But the weird thing about such constants is that there is no theory to explain their existence. They are universal and they appear to be unchanging. So is the case with the masses of protons and electrons. But time and time again, they are validated through observation and experiment, not theory.
.. Paul Dirac, wondered in a Nature paper whether the constants were indeed constant if one were to look at the entire history of the cosmos. Measurements on earth are useful but it is a tiny blue dot in the vast universe. What Dirac asked decades ago is what physicists continue to ask today. Is it a constant everywhere in the universe? Why is it a constant? How constant?
.. The mass ratio, they write, varies less than 0.0005 percent, not enough to call it a change. This is based on telescope observations going as far as 12.4 billion years back in time when the universe was only 10 percent of its current age.
.. Even a small change of a few percent in the value of the ratio would mean a different universe. A smaller mass ratio could mean a wimpier proton, and possibly a weaker pull for the electrons orbiting the nucleus, leading to different kind of matter.
.. No theory in physics can explain the constant mass ratio, the steadfast shepherd of science. It just is, *shrug*.
.. The experimental search for a varying constant will likely continue as long as there is no theory to back its existence.