# Bra-ket notation: Quiz

Question 1: Bra-ket notation is a standard notation for describing quantum states in the theory of ________ composed of angle brackets and vertical bars.
Schrödinger equationIntroduction to quantum mechanicsWave–particle dualityQuantum mechanics

Question 2: The notation was introduced in 1939 by ________, and is also known as Dirac notation.
Quantum mechanicsPaul DiracWave–particle dualityIntroduction to quantum mechanics

Question 3: By the definition of addition and scalar multiplication of linear functionals in the ________,
Linear mapHilbert spaceDual spaceVector space

Question 4: One of the uses of the outer product is to construct ________.
Vector spaceEigenvalue, eigenvector and eigenspaceDual spaceProjection (linear algebra)

Question 5: (The exception to this is if the subsystems are actually ________.
FermionQuantum mechanicsIdentical particlesPhoton

Question 6: For example, observable physical quantities are represented by self-adjoint operators, such as ________ or momentum, whereas transformative processes are represented by unitary linear operators such as rotation or the progression of time.
ForceEnergyUniverseSpace

Question 7: In what follows, c1 and c2 denote arbitrary ________, c* denotes the complex conjugate of c, A and B denote arbitrary linear operators, and these properties are to hold for any choice of bras and kets.
Vector spaceReal numberField (mathematics)Complex number

Question 8: It is usually taken as a postulate or ________ of quantum mechanics, that any operator corresponding to an observable quantity (shortly called observable) is self-adjoint, that is, it satisfies A = A.
Axiomatic systemSet theoryAxiomMathematical logic

Question 9: For instance, the ________ operator p has the following form:
ForceEnergyClassical mechanicsMomentum

Question 10: This process is very similar to the use of coordinate vectors in ________.
Eigenvalue, eigenvector and eigenspaceLinear algebraVector spaceMatrix (mathematics)