##### Asked by: Fabian Hatheway

## What is the physical significance of two operators commute?

If two operators commute then **both quantities can be measured at the same time with infinite precision**, if not then there is a tradeoff in the accuracy in the measurement for one quantity vs. the other. This is the mathematical representation of the Heisenberg Uncertainty principle.

Mar 18, 2020

## When two operators commute What can we say about their Eigenfunctions?

a. Hence commuting operators have simultaneous eigen- states. That is these can be exactly measured simultaneously. (By extension two operators that do not commute cannot be measured simultaneously as we will see in the next sec- tion. )

## What do you mean by spin angular momentum?

“Spin is **the total angular momentum, or intrinsic angular momentum, of a body**. The spins of elementary particles are analogous to the spins of macroscopic bodies. In fact, the spin of a planet is the sum of the spins and the orbital angular momenta of all its elementary particles.

Oct 21, 1999

## What are non commuting operators?

Non-commuting operators in quantum mechanics

, so again **the operators do not commute** and the physical meaning is that the position and linear momentum in a given direction are complementary.

## What is the physical significance of an operator commuting with the Hamiltonian?

Now: Operators or observables that commute with the Hamiltonian of the system are **conserved quantities**, e.g. angular momentum or spin. This means that these quantities do not change with time. Those that do not commute with the Hamiltonian, are not conserved quantities.

Feb 21, 2021

## Do commuting operators have common eigenfunctions?

, **have a common set of eigenfunctions**, provided only that each has a complete set of eigenfunctions.

## Does an operator commute with itself?

Properties of commutators

**Any operator commutes with itself** [A, A] = 0, with any power of itself [A, A^{n}] = 0 and with any function of itself [A,f(A)]=0 (from previous property and with power expansion of any function).

Mar 3, 2022

## Do commuting operators have common eigenvalues?

Commuting Operators Have the Same Eigenvectors, but **not Eigenvalues**.

Apr 28, 2019

## Is spin angular momentum constant?

Any change in the spin angular momentum of a system whose total angular momentum is conserved is matched by an equal and opposite change in the orbital angular momentum of the system.

Wave Equations for Low Spin in Minkowski spacetime.

Spin, mass | Wave equation | Associated particles |
---|---|---|

s = 1, m > 0 | Proca eqn. | Vector mesons |

## Why is spin angular momentum important?

Angular momentum **plays an important role in quantum mechanics**, not only as the orbital angular momentum of electrons orbiting the central potentials of nuclei, but also as the intrinsic magnetic moment of particles, known as spin, and even as isospin in high-energy particle physics.

Nov 25, 2021

## Is spin a relativistic effect?

**Spin is not only explained by relativistic quantum mechanics**. Spinors are described by the Dirac equation, but angular momentum was pat of the mathematics of quantum mechanics since its beginnings. Spin is just the intrinsic angular momentum of a particle. That’s why you can add →S and →L to get →J in the first place.

Jul 24, 2017

## What is the physical significance of Hamiltonian?

The Hamiltonian of a system **specifies its total energy—i.e., the sum of its kinetic energy (that of motion) and its potential energy (that of position)**—in terms of the Lagrangian function derived in earlier studies of dynamics and of the position and momentum of each of the particles.

## Which operators commute with the Hamiltonian?

**Angular momentum operator L** commutes with the total energy Hamiltonian operator (H).

## How do you show that the operators commute?

Quote from video: *So in this example we use kinetic energy operator and the momentum operator in the X direction if these two operators commute that means first of all mathematically. Speaking the order of operation.*

## How do you find the commutator of two operators?

Definition: Commutator

The Commutator of two operators A, B is the operator C = [A, B] such that **C = AB − BA**.

Mar 3, 2022

## How do you know if an operator is commute?

Quote from video: *If you get the same function after those two operations. Then you say the two operators commute. If on the other hand.*

## Which of the following operators commute?

Answer and Explanation: Operator commute with itself and its power. So, **x and x2** commute with each other.

## What is commutation physics?

A commutator is **a piece of equipment linked to the armature of such a motor as well as a dynamo that makes an electrical linkage as well as guarantees the amount of current flowing via direct current**.

## Why commutator is needed?

On DC and most AC motors the purpose of the commutator is **to insure that the current flowing through the rotor windings is always in the same direction, and the proper coil on the rotor is energized in respect to the field coils**.

## How do you evaluate a commutator?

Quote from video: *So for commutator x' if a and B commute. Then we can do this operation in either order. So a B acting on F then a acting on F would be equal to a acting on F then B acting on F.*