quantum physics
posted by Anonymous
8(a) Consider a spin qubit in the state 3ã20⟩+121⟩. What are the coordinates (ƒÆ,ϕ) of this qubit on the Bloch sphere?
ƒÆ=?
ϕ=?
8b. We turn on a magnetic field in the z^ direction at time t=0. This corresponds to the Hamiltonian H=BZ, where B is a constant and Z is the usual phase flip. What is the state of our qubit at time t as a function of B and t?
8c. What are the coordinates (ƒÆ,ϕ) of this qubit on the Bloch sphere at time t, as a function of B and t?
8d. Now suppose we start with the qubit ƒÕ(0)⟩=0⟩ and we apply a magnetic field in the x^ direction at t=0. This corresponds to the Hamiltonian H=BX, where B is a constant and X is the usual bit flip gate. What are the coordinates (ƒÆ,ϕ) of this qubit on the Bloch sphere at time t, as a function of B and t?
ƒÆ=?
ϕ=?

Anonymous
please help!!

david
D
ƒÆ = 2Bt
phi = pi/2
C  pi/3; 2*B*t
do you need explanation ? 
Anonymous
@ David thanks but its wrong for d.

Anonymous
can you explain..please

ss01
try ƒÆ = 2Bt
and phi = 0 
david
sorry for that
@ss01 your phi is wrong that i am for sure it cannot be 0 
david
got my error
8d ƒÆ= 0 and ϕ = 2bt
check and tell me if i am right?
8a ƒÆ = pi/3 and ϕ = 0 
stuart
r u right,david abt 8d?

stuart
r u right,david abt 8d?and wat abt 8 b?

david
ya, this time

david
doing 8b

stuart
its wrong.8 d,

Anonymous
please help with 8d!!

Anonymous
8b:
e^(i*B*t)*sqrt(3)/2
e^(i*B*t)/2
please help with Q8D please 
Tu papi
8D
θ= 2⋅B⋅t
ϕ= 3⋅π/2
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