Quotes About Quantum

In fact, it was specifically for discovering the law of the photoelectric effect that Einstein would win his only Nobel Prize.

According to the assumption to be considered here, when a light ray is propagated from a point, the energy is not continuously distributed over an increasing space but consists of a finite number of energy quanta which are localized at points in space and which can be produced and absorbed only as complete units.

The resulting four-page paper, published in May 1935 and known by the initials of its authors as the EPR paper, was the most important paper Einstein would write after moving to America. "Can the Quantum-Mechanical Description of Physical Reality Be Regarded as Complete?" they asked in their title.

quantum moments are always benevolent.

Everything in the universe is energy, including you. All of the things that constitute your body are really a form of energy. They are just resonating at a certain frequency and appear to be solid because of that frequency.

Zero dwells at the juxtaposition of quantum mechanics and relativity; zero lives where the two theories meet, and zero causes the two theories to clash. A black hole is a zero in the equations of general relativity; the energy of the vacuum is a zero in the mathematics of quantum theory. The big bang, the most puzzling event in the history of the universe, is a zero in both theories. The universe came from nothing-and both theories break down when they try to explain the origin of the cosmos.

Physicists now know that 70 per cent of the known universe is dark energy. Dark matter is another 25 per cent. Once we thought we knew all about life, but it turns out everything we think of as reality is less than 5 per cent.

A new philosophy emerged called quantum physics, which suggest that the individual's function is to inform and be informed. You really exist only when you're in a field sharing and exchanging information. You create the realities you inhabit.

The loop approach to quantum gravity is now a thriving field of research. Many of the older ideas, such as supergravity and the study of quantum black holes, have been incorporated into it. Connections have been discovered to other approaches to quantum gravity, such as Alain Connes's non-commutative approach to geometry, Roger Penrose's twistor theory and string theory.

The key question for a quantum theory of gravity is then the following: Can we extend to quantum theory the principle that space has no fixed geometry? That is, can we make quantum theory background-independent, at least with regard to the geometry of space? If we can do this, we will automatically merge gravity and quantum theory, because gravity is already understood to be an aspect of dynamical spacetime geometry.

A quantum state is a useful tool because it can do just that. This is our next principle: Given the quantum state of an isolated system at one time, there is a law that will predict the precise quantum state of that system at any other time. This law is called Rule 1. It is also sometimes called the Schrödinger equation. The principle that there is such a law is called unitarity.

When we make a measurement on a system, we disturb it, typically by forcing it to interact with a measuring instrument. So Rule 1 does not apply to measurements. This is true not only of measurements, but of any interaction between the system and outside forces. So is there anything special about measurements? Measurements are special because they are where probabilities enter quantum theory.

These last few points are key to how quantum mechanics works, so let me summarize them: The wave represents the quantum state. When we leave the system alone, it changes in time deterministically, according to Rule 1. But the quantum state is only indirectly related to what we observe when we make a measurement, and that relation is not deterministic. The relation between the quantum state

The pilot wave theory predicts everything quantum mechanics does, but explains a good deal more. The mysterious way in which the ensemble seems to influence the individual is cleared up and explained straightforwardly as the influence of the wave on the particle. Both are real, and both exist for every individual atom. Everything that was puzzling and mysterious about quantum mechanics is revealed to be a consequence of that theory leaving out half of every story. Despite

These last few points are key to how quantum mechanics works, so let me summarize them: The wave represents the quantum state. When we leave the system alone, it changes in time deterministically, according to Rule 1. But the quantum state is only indirectly related to what we observe when we make a measurement, and that relation is not deterministic. The relation between the quantum state and what we observe is probabilistic. Randomness enters in a

But, even if the quantum state gives us only probabilities for what we observe, once we get a result, there is something that is definite, because afterward you know exactly what the state is. It is the state corresponding to the result obtained by the measurement. Suppose we measure an electron's momentum, and get the result that the electron is moving north with momentum 17 (in some units). Then, just after the measurement we know that the

17. This is enshrined in a second rule,fn2 which we call Rule 2: The outcome of a measurement can only be predicted probabilistically. But afterward, the measurement changes the quantum state of the system being measured, by putting it in the state corresponding to the result of the measurement. This is called collapse of the wave function.

Rule 2 raises a whole bunch of questions. Does the wave function collapse abruptly or does it take some time? Does the collapse take place as soon as the system interacts with the detector? Or only later, when a record is made? Or perhaps later still, when it is perceived by a conscious mind? Is the collapse a physical change, which means that the quantum state is real? Or is it just a change in our knowledge of the system, which means the

quantum state is only a representation of that knowledge? How does a system know a particular interaction has taken place with a detector, so that it should then, and only then, obey Rule 2? What happens if we combine the original system and the detector into a larger system? Does Rule 1 then apply to the whole system? These questions

Problem 1: Combine general relativity and quantum theory into a single theory that can claim to be the complete theory of nature. This is called the problem of quantum gravity.

Besides the argument based on the unity of nature, there are problems specific to each theory that call for unification with the other. Each has a problem of infinities. In nature, we have yet to encounter anything measurable that has an infinite value. But in both quantum theory and general relativity, we encounter predictions of physically sensible quantities becoming infinite. This is likely the way that nature punishes impudent theorists who dare to break her unity.

The wavelength of a lightwave limits how small a thing you can see, for you cannot resolve an object smaller than the wavelength of the light you use to see it. Hence, one cannot detect the existence of an extra dimension smaller than the wavelength of light one can perceive.

Do I care about these other branches? Should I? There is always the chance that at some time in the future an empty branch recombines with my branch, causing interference, which changes my life

But were we mere atoms, interference between full and empty branches of the wave function would be happening all the time.