Hitch in Quantum Mechanics

 

A hidden property of corkscrew, spiraled beams of light could put a hitch in quantum mechanics.

The photons, or light particles, inside these light-based Möbius strips spin with a momentum previously thought to be impossible. The findings could shake up some of the assumptions in quantum mechanics, the rules that govern the menagerie of tiny subatomic particles.

“This is a sort of fairly basic property of light, and we’ve shown it’s not working the way people thought it would,” said study co-author Paul Eastham, a physicist at Trinity College Dublin in Ireland. [Wacky Physics: The Coolest Little Particles in Nature]

Hollow beams of light

The research was spurred by findings from roughly two centuries ago, when Irish physicist and astronomer William Hamilton and his colleague Humphrey Lloyd predicted that crystals with certain internal arrangements of their atoms would create a hollow tube of light if the incident light hit the crystal at just the right angle.

In honor of the 200th anniversary of this discovery, Eastham and his colleagues decided to probe the theoretical underpinnings of this phenomenon. He began to wonder what this type of hollow light beam implied for the angular momentum, or spin, of light particles that made up the ray. As he worked through the math, he realized something strange: The photons inside the conical ray would have an angular momentum of one-half of Planck’s constant, the fundamental constant that governs the relationship between energy and wavelength.

But that seemed impossible, given that the equations of quantum mechanics implied that light particles could have spins that were multiples of the fundamental constant (for instance, twice Planck’s constant, negative three times Planck’s constant, and so on).

 

Half-spin photons

To see if his calculations would be borne out in reality, the team tested the theory. They sent a laser beam through a crystal at a precise angle, and then used a mainstay optical device called an interferometer to split the beams of light and sort them according to their spin.

Sure enough, the photons, when measured, had angular momentums equal to one-half Planck’s constant and minus one-half Planck’s constant, respectively, the researchers reported online April 29 in the journal Science Advances.

The findings are fascinating because they imply that light particles don’t behave as they’re predicted to, said study co-author Kyle Ballantine, a physicist at Trinity College Dublin.

“All particles can be divided into two fundamental groups: Bosons, including photons in all measurements to date, have integer [whole number] angular momentum; and fermions [such as electrons] have half-integer,” Ballantine told Live Science in an email. “This distinction leads to very different quantum behavior. Our result shows that we can make beams of photons which behave like fermions, a completely different form of matter.”

Still, the new results don’t reduce the significance of Planck’s constant or tear down the entire edifice of subatomic physics, Eastham said.

“We haven’t broken quantum mechanics,” Eastham told Live Science.

However, the results are still so new that it’s not clear exactly what they suggest, Eastham said. One immediate implication: The findings could affect quantum computing and cryptography, both of which would rely on statistics regarding subatomic particles that may need to be rethought, he said.

Spooky Action at a Distance

 

This is the actual information as published by the author

An Explanation of Bell’s Theorem

Copyright (c) 1999 by Gary Felder

I. Introduction

There are many aspects of modern physics which seem to violate our intuition. The classical theory of physics which was held from the time of Newton until this century provided an orderly model of a world made of objects moving around and pushing each other around in predictable ways. The mathematics could be difficult, but the basic ideas meshed with our common sense notions of how the world works. Starting at the beginning of this century, our physical theories began to include aspects which ran counter to that common sense, and yet the theories consistently made accurate predictions of experiments which could not be explained with Newtonian physics. Gradually, and despite much resistance, physicists have been forced to accept these new results.

In this paper I am going to discuss one of those results, called nonlocality. Its converse, locality, is the principle that an event which happens at one place can’t instantaneously affect an event someplace else. For example: if a distant star were to suddenly blow up tomorrow, the principle of locality says that there is no way we could know about this event or be affected by it until something, e.g. a light beam, had time to travel from that star to Earth. Aside from being intuitive, locality seems to be necessary for relativity theory, which predicts that no signal can propagate faster than the speed of light.

Quotes

 

“I have to act like a decent human being, and you know what a strain that puts on me”

– Greg House

Castle - Season Finale

Hollander's Woods

Release Date

12 May 2015

 

Promo

 

 

Song #28

Outside by Ellie Goulding

 

Magnetic Monopole’s contribution in Our Understanding of the Universe

 

You’ve probably heard of the Higgs boson. This elusive particle was predicted to exist long ago and helped explain why the Universe works the way it does, but it took decades for us to detect.Well, there’s another elusive particle that has also been predicted by quantum physics, and it’s been missing for an even longer time. In fact, we still haven’t spotted one, and not through lack of trying. It’s called the magnetic monopole, and it has a few unique properties that make it rather special.

 

Those with an interest in physics are probably already familiar with an electric monopole, although you may know it by its more common name: electric charge.

Opposite electric charges attract and like charges repel through the interaction of electric fields, which are defined as running from positive to negative. These are the somewhat arbitrary labels for the two opposing electric charges.Electric monopoles exist in the form of particles that have a positive or negative electric charge, such as protons or electrons.

At first glance, magnetism seems somewhat analogous to electricity, as there exists a magnetic field with a direction defined as running from north to south.However, the analogy breaks down when we try to find the magnetic counterpart for the electric charge. While we can find electric monopoles in the form of charged particles, we have never observed magnetic monopoles.

Instead, magnets exist only in the form of dipoles with a north and a south end. When a bar magnet is split into two pieces, you don’t get a separate north part and a south part. Rather you get two new, smaller magnets, each with a north and south end.

Even if you split that magnet down into individual particles, you still get a magnetic dipole.When we look at magnetism in the world, what we see is entirely consistent with Maxwell’s equations, which describe the unification of electric and magnetic field theory into classical electromagnetism.

They were first published by James Maxwell during 1861 and 1862 and are still used daily on a practical level in engineering, telecommunications and medical applications, to name just a few.

But one of these equations – Gauss’s law for magnetism – states that there are no magnetic monopoles.The magnetism we observe on a day-to-day basis can all be attributed to the movement of electric charges. When an electrically charged particle moves along a path, such as an electron moving down a wire, this is an electrical current. This induces a magnetic field that wraps around the direction of the current.

The second cause of magnetism involves a property from quantum mechanics called ‘spin’. This can be thought of in terms of an electrically charged particle rotating on an axis rather than moving in a particular direction.This generates an angular momentum in the particle, causing the electron to act as a magnetic dipole (i.e. a tiny bar magnet). This means we can describe magnetic phenomena without the need for magnetic monopoles.

But just because our classical electromagnetic theories are consistent with our observations, that does not imply that there are no magnetic monopoles. Rather, this just means that there are no magnetic monopoles anywhere that we have observed.

Once we start to delve into the murky depths of theory, we begin to find some tempting arguments for their presence in the Universe.

The lure of duality

 

In 1894, Nobel Laureate Pierre Curie discussed the possibility of such an undiscovered particle and could find no reason to discount its existence.Later, in 1931, Nobel Laureate Paul Dirac showed that when Maxwell’s equations are extended to include a magnetic monopole, electric charge can exist only in discrete values.

This ‘quantisation’ of electric charge is one of the requirements of quantum mechanics. So Dirac’s work went towards showing that classical electromagnetism and quantum electrodynamics were compatible theories in this sense.

Finally, there are few physicists who can resist the beauty of symmetry in nature. And because the existence of a magnetic monopole would imply a duality between electricity and magnetism, the theory suggesting magnetic monopoles becomes almost intoxicating.

Duality, in the physical sense, is when two different theories can be related in such a way that one system is analogous to the other.

If it were the case that the electric force was completely analogous to the magnetic force, then perhaps other forces would also be analogous to one another. Perhaps then there would be some way to relate the strong nuclear force to the weak nuclear force, paving the way to a grand unification of all physical forces.

Of course, just because an hypothesis has an appealing symmetry doesn’t make it correct.

A single magnetic monopole might be hiding out there somewhere.

 

Monopole mirage

 

Scientists have come close to seeing magnetic monopoles by producing monopole-like structures in the lab using complex arrangements of magnetic fields in Bose-Einstein condensates and superfluids.But, while these show that a magnetic monopole is not a physical impossibility, they are not the same as discovering one in nature.Particle physics experiments have, on occasion, announced possible monopole candidates, but so far none of these discoveries have been shown to be irrefutable or reproducible.

The Monopole and Exotics Detector at the Large Hadron Collider (MoEDAL) has taken up the search, but has found no monopoles to date.

As a result, magnetic monopole enthusiasts have turned their sights to explaining why we haven’t seen any monopoles.If the current generation of particle accelerators have failed to detect a magnetic monopole, perhaps the mass of a monopole is simply greater than we are able to create at present.

Using theory, we can estimate the maximum possible mass for the magnetic monopole. Given what we already know about the structure of the Universe, we can estimate that the monopole mass could be up to an enormous 1014 TeV.

An object this massive may have been produced only in the very early stages of the Universe after the Big Bang, before cosmic inflation began.

 

If the Universe cooled to a point that monopole creation was no longer energetically possible before expanding, perhaps the monopoles are out there. Just few and far between. The trick is to find one.

Source: http://www.sciencealert.com/we-re-missing-a-magnetic-monopole-and-our-understanding-depends-on-it

Quiz Question #31

 

Q) In the Ecole Nationale Institute in France, a group of students created a software X. While they did so, other members used to go out to the streets of Paris and collect Y from the streets. By the time the software was done, they had hundreds of Ys. Hence the logo of X became Y.

• X – VLC Media Player
• Y – Cones

Question Credits Shreyas Ashok Kumar