What is a probability amplitude?

In summary, the probability amplitude is a solution to an equation, such as the Schrodinger equation, and when squared, it represents the probability of a certain state or outcome. It is a complex number that is used to predict real-world probabilities.
  • #1
Carnot
19
0
Hi

What is a probability amplitude - I have read the article on wikipedia and I still don't get it.
Hope someone out there can explain it to me..

Thanks
 
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  • #2
The probability amplitude is the solution of some equation, such as the wave equation. When it is squared (absolute value) it is interpreted as a probability. Don't try to look for a deeper meaning.
 
  • #3
mathman said:
The probability amplitude is the solution of some equation, such as the wave equation. When it is squared (absolute value) it is interpreted as a probability. Don't try to look for a deeper meaning.
Would be a bit more accurate to say the probability amplitude function is a solution to the Schrodinger equation (the probability amplitude function is the system's "quantum state"), but this function gives a set of different probability amplitudes for different possible eigenstates of some observable quantity, like different position eigenstates. For each possible position (or set of positions for a collection of multiple particles), the function would assign a complex number (say, 2 + 3i) to that position(s) which would be the "probability amplitude" for that particular position(s). And if you make a position measurement, the square of the probability amplitude for any particular position eigenstate (really the complex conjugate of the probability amplitude, like [2 + 3i]*[2 - 3i]) gives the probability the particle (or collection of particles) will be found in that position(s). No one knows why you have to go through this arcane procedure of finding the time evolution of the probability amplitude and taking the complex conjugate at the moment of measurement to get the probabilities of different measurement results, it's just that this procedure seems to be the correct way to predict real-world probabilities.
 
  • #4
That made it a bit clearer :-)

Thanks a lot both of you
 

1. What is a probability amplitude?

A probability amplitude is a complex number that represents the likelihood of a specific outcome occurring in a quantum system. It is a fundamental concept in quantum mechanics, where it is used to calculate the probability of a particle or system being in a certain state.

2. How is a probability amplitude different from a probability?

While a probability represents the chance of a specific outcome occurring in classical physics, a probability amplitude in quantum mechanics takes into account the wave-like nature of particles and can have both positive and negative values. The square of the absolute value of the probability amplitude gives the probability of the outcome.

3. What is the relationship between probability amplitudes and wavefunctions?

Probability amplitudes and wavefunctions are closely related in quantum mechanics. The wavefunction is a mathematical function that describes the quantum state of a system, and the probability amplitude is the coefficient of the wavefunction for a particular state. The square of the absolute value of the wavefunction gives the probability density of finding the system in a specific state.

4. How are probability amplitudes used in quantum computing?

In quantum computing, probability amplitudes are used to represent the state of qubits, which are the basic units of quantum information. By manipulating these probability amplitudes through quantum gates, quantum algorithms can perform calculations and solve problems with greater efficiency than classical computers.

5. How are probability amplitudes calculated?

The calculation of probability amplitudes in quantum mechanics involves using mathematical tools such as the Schrödinger equation and the principle of superposition. These tools allow scientists to determine the probability of a quantum system being in a specific state, and thus make predictions about the behavior of particles and systems at the quantum level.

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