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Authors: Marcus Chown
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in the garage before daybreak.
In practice, mass is conjured out of empty space in the form of microscopic particles of matter. The quantum vacuum is actually a seething morass of microscopic particles such as electrons poppinginto existence and then vanishing again. 4 And this is no mere theory. It actually has observable consequences. The roiling sea of the quantum vacuum actually buffets the outer electrons in atoms, very slightly changing the energy of the light they give out. 5
The fact that the laws of nature permit something to come out of nothing has not escaped cosmologists, people who think about the origin of the Universe. Could it be, they wonder, that the entire Universe is nothing more than a quantum fluctuation of the vacuum? It’s an extraordinary thought.
1 See Chapter 8, “ E = mc 2 and the Weight of Sunshine.”
2 See Chapter 7, “The Death of Space and Time.”
3 See Chapter 8, “ E = mc 2 and the Weight of Sunlight.”
4 Actually, every particle created is created alongside its antiparticle, a particle with opposite properties. So a negatively charged electron is always created with a positively charged positron.
5 This effect is called the Lamb shift.
5
T HE T ELEPATHIC U NIVERSE
H OW ATOMS CAN INFLUENCE EACH OTHER INSTANTLY EVEN WHEN ON OPPOSITE SIDES OF THE UNIVERSE
Beam me up, Mr. Scott.
Captain James T. Kirk
A coin is spinning. The coin is in a strong box sitting in the mud at the bottom of the deepest ocean trench. Don’t ask what has set the coin spinning or what is keeping it spinning. This isn’t a well-thought-out story! The point is that there is an identical spinning coin in an identical box sitting on a cold moon in a distant galaxy on the far side of the Universe.
The first coin comes down heads. Instantaneously, without the merest split-second of delay, its cousin 10 billion light-years from Earth comes down tails.
The coin on Earth could equally well have come down tails and its distant cousin heads. This is not important. The significant thing is that the coin on the far side of the Universe knows instantly the state of its distant terrestrial cousin—and does the opposite.
But how can it possibly know? The cosmic speed limit in our Universe is the speed of light. 1 Since the coins are separated by 10 billion light-years, information about the state of one coin must takea minimum of 10 billion years to reach the other. Yet they know about each other in a split second.
This kind of “spooky action at a distance” turns out to be one of the most remarkable features of the microscopic world. It so upset Einstein that he declared that quantum theory must be wrong. In fact, Einstein was wrong.
In the past 20 years, physicists have observed the behaviour of coins that are separated by large distances. The coins are quantum coins, and the distances are not of course as large as the width of the Universe. 2 Nevertheless, the experiments have successfully demonstrated that atoms and their kin can indeed communicate instantaneously, in total violation of the speed-of-light barrier.
Physicists have christened this weird kind of quantum telepathy nonlocality. The best way to understand it is by considering a peculiar particle property called spin.
SPOOKY ACTION AT A DISTANCE
Spin is unique to the microscopic world. Particles that possess spin behave as if they are rotating like tiny spinning tops. Only they aren’t actually spinning! Once again, we come up against the fundamental ungraspability of the microscopic world. The spin of particles, like their inherent unpredictability, is something with no direct analogue in the everyday world. Microscopic particles can have different amounts of spin. The electron happens to carry the minimum quantity.This permits it to spin in two possible ways. Think of it as spinning either clockwise or anticlockwise (although of course it isn’t actually spinning at all!).
If two electrons are created together—the first with clockwise
In practice, mass is conjured out of empty space in the form of microscopic particles of matter. The quantum vacuum is actually a seething morass of microscopic particles such as electrons poppinginto existence and then vanishing again. 4 And this is no mere theory. It actually has observable consequences. The roiling sea of the quantum vacuum actually buffets the outer electrons in atoms, very slightly changing the energy of the light they give out. 5
The fact that the laws of nature permit something to come out of nothing has not escaped cosmologists, people who think about the origin of the Universe. Could it be, they wonder, that the entire Universe is nothing more than a quantum fluctuation of the vacuum? It’s an extraordinary thought.
1 See Chapter 8, “ E = mc 2 and the Weight of Sunshine.”
2 See Chapter 7, “The Death of Space and Time.”
3 See Chapter 8, “ E = mc 2 and the Weight of Sunlight.”
4 Actually, every particle created is created alongside its antiparticle, a particle with opposite properties. So a negatively charged electron is always created with a positively charged positron.
5 This effect is called the Lamb shift.
5
T HE T ELEPATHIC U NIVERSE
H OW ATOMS CAN INFLUENCE EACH OTHER INSTANTLY EVEN WHEN ON OPPOSITE SIDES OF THE UNIVERSE
Beam me up, Mr. Scott.
Captain James T. Kirk
A coin is spinning. The coin is in a strong box sitting in the mud at the bottom of the deepest ocean trench. Don’t ask what has set the coin spinning or what is keeping it spinning. This isn’t a well-thought-out story! The point is that there is an identical spinning coin in an identical box sitting on a cold moon in a distant galaxy on the far side of the Universe.
The first coin comes down heads. Instantaneously, without the merest split-second of delay, its cousin 10 billion light-years from Earth comes down tails.
The coin on Earth could equally well have come down tails and its distant cousin heads. This is not important. The significant thing is that the coin on the far side of the Universe knows instantly the state of its distant terrestrial cousin—and does the opposite.
But how can it possibly know? The cosmic speed limit in our Universe is the speed of light. 1 Since the coins are separated by 10 billion light-years, information about the state of one coin must takea minimum of 10 billion years to reach the other. Yet they know about each other in a split second.
This kind of “spooky action at a distance” turns out to be one of the most remarkable features of the microscopic world. It so upset Einstein that he declared that quantum theory must be wrong. In fact, Einstein was wrong.
In the past 20 years, physicists have observed the behaviour of coins that are separated by large distances. The coins are quantum coins, and the distances are not of course as large as the width of the Universe. 2 Nevertheless, the experiments have successfully demonstrated that atoms and their kin can indeed communicate instantaneously, in total violation of the speed-of-light barrier.
Physicists have christened this weird kind of quantum telepathy nonlocality. The best way to understand it is by considering a peculiar particle property called spin.
SPOOKY ACTION AT A DISTANCE
Spin is unique to the microscopic world. Particles that possess spin behave as if they are rotating like tiny spinning tops. Only they aren’t actually spinning! Once again, we come up against the fundamental ungraspability of the microscopic world. The spin of particles, like their inherent unpredictability, is something with no direct analogue in the everyday world. Microscopic particles can have different amounts of spin. The electron happens to carry the minimum quantity.This permits it to spin in two possible ways. Think of it as spinning either clockwise or anticlockwise (although of course it isn’t actually spinning at all!).
If two electrons are created together—the first with clockwise
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