Ovidio Universe: Entanglement

December 07, 2020

Entanglement

Che cos'è l'Entanglement?

Even more surprising than superposition, quantum theory predicts that entities may have correlated fates. That is, the result of a measurement on one photon or atom leads instantaneously to a correlated result when an entangled photon or atom is measured.

For a more intuitive grasp of what we mean by “correlated results,” imagine that two coins could be entangled (there is no known way of doing this with coins, of course). Imagine one is tossing a coin. Careful records show it comes up “heads” about half the time and “tails” half the time, but any one result is unpredictable. Tossing another coin has similar, random results, but surprisingly, the records of the coin tosses show a correlation! When one coin comes up heads, the other coin comes up tails and vice versa. We say that the state of the two coins is entangled. Before the measurement (the toss), the outcome is unknown, but we know the outcomes will be correlated. As soon as either coin is tossed (measured), the fate of tossing the other coin is sealed. We cannot predict in advance what an individual coin will do, but their results will be correlated: once one is tossed, there is no uncertainty about the other.

This imaginary coin tossing is only to give the reader a sense of entanglement. Although one might come up with a classical explanation for these results, multitudes of ingenious experiments have confirmed the existence of entanglement and ruled out any possible classical explanation. Over several decades, physicists have continually refined these experiments to remove loopholes in measurement accuracy or subtle assumptions. All have confirmed the predictions of quantum mechanics.

With actual particles any measurement collapses uncertainty in the state. A real experiment would manufacture entangled particles, say by bringing particles together and entangling them or by creating them with entangled properties. For instance, we can “downconvert” one higher energy photon into two lower energy photons which leave in directions not entirely predictable. Careful experiments show that the directions are actually a superposition, not merely a random, unknown direction. However, since the momentum of the higher energy photon is conserved, the directions of the two lower energy photons are entangled. Measuring one causes both photons to collapse into one of the measurement bases. However, once entangled, the photons can be separated by any distance, at any two points in the universe; yet measuring one will result in a perfectly correlated measurement for the other.

Even though measurement brings about a synchronous collapse regardless of the separation, entanglement doesn’t let us transmit information. We cannot force the result of a measurement any more than we can force the outcome of tossing a fair coin (without interference).

Source:www.sciencedirect.com

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Black Holes and Wormholes FAQ

1 - What is a wormhole?

Wormholes are tunnels in space-time that can theoretically allow travel anywhere in space and time, or even into another universe. In many ways, wormholes resemble black hole.

2- How is wormhole created?

In principle, building a wormhole is pretty straightforward. According to Einstein's Theory of General Relativity, mass and energy warp the fabric of space-time. And a certain special configuration of matter and energy allows the formation of a tunnel, a shortcut between two otherwise distant portions of the universe

3- Is a wormhole possible?

A physicist has shown that wormholes can exist: tunnels in curved space-time, connecting two distant places, through which travel is possible.

4- Can black holes be wormholes?

From the outside, wormholes can appear similar to black holes. But while an object that falls into a black hole is trapped there, something that falls into a wormhole could traverse through it to the other side. No evidence has been found that wormholes exist

Baryon Matter

Baryon matter is the foundation that 
constitutes every body and object in 
our Universe. 
To better understand how it is structured, 
it is necessary to refer to the classification 
scheme  of the Standard Model as it has 
been structured over the last century.  
The Standard Model predicts that matter 
is basically the product of two types of
particles,light ones,leptons, and heavy ones, 
baryons. 
Both terms derive from the Greek. 
While leptons are truly fundamental particles, 
i.e. not further divisible into other particles, 
baryons are aggregates of other elementary 
particles such as leptons, quarks that are 
endowed with fractional charge,
 i.e. a fraction of the charge of an electron.

Light Year

The light-year is a unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometres (9.46×10¹² km) or 5.88 trillion miles (5.88×10¹² mi).As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days).Because it includes the word "year", the term light-year may be misinterpreted as a unit of time.

The light-year is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications.

1 light-year	= 9460730472580800 metres (exactly)
	≈ 9.461 petametres
	≈ 9.461 trillion kilometres (5.879 trillion miles)
	≈ 63241.077 astronomical units
	≈ 0.306601 parsecs

What is the antimatter

The antimatter is missing – not from CERN, but from the Universe! At least that is what we can deduce so far from careful examination of the evidence. For each basic particle of matter, there exists an antiparticle with the same mass, but the opposite electric charge. The negatively charged electron, for example, has a positively charged antiparticle called the positron. When a particle and its antiparticle come together, they both disappear, quite literally in a flash, as the annihilation process transforms their mass into energy.

The evidence spoke for itself

The ‘case file’ of antimatter was opened in 1928 by physicist Paul Dirac. He developed a theory that combined quantum mechanics and Einstein’s special relativity to provide a more complete description of electron interactions. The basic equation he derived turned out to have two solutions, one for the electron and one that seemed to describe something with positive charge (in fact, it was the positron). Then in 1932 the evidence was found to prove these ideas correct, when the positron was discovered occurring naturally in cosmic rays.

For the past 50 years and more, laboratories like CERN have routinely produced antiparticles, and in 1995 CERN became the first laboratory to create anti-atoms artificially. But no one has ever produced antimatter without also obtaining the corresponding matter particles. The scenario should have been the same during the birth of the Universe, when equal amounts of matter and antimatter would have been produced in the Big Bang.

“Just one more thing…”

So if matter and antimatter annihilate, and we and everything else are made of matter, why do we still exist? This mystery arises because we find ourselves living in a Universe made exclusively of matter. Didn't matter and antimatter completely annihilate at the time of the Big Bang? Perhaps this antimatter still exists somewhere else? Otherwise where did it go and what happened to it in the first place?

Such questions have led to speculative theories, from a break in the rules to the existence of an entire anti-Universe somewhere else! The way to solve the baffling disappearance of antimatter, and to learn more about this substance in general, is by studying both particles and antiparticles to find and decipher the subtle clues.