Incorrect return state and expectation value for time evolution solvers with trivial `tlist`

[ytdHuang]

Bug Description

Usually no one will specify tlist = [0, 0], but somehow this is still a bug because the number of states and the values of expect will be incorrect.

Code to Reproduce the Bug

tlist = [0, 0]
sol = sesolve(sigmax(), basis(2, 0), tlist)
println(sol.states, "\n")

sol = sesolve(sigmax(), basis(2, 0), tlist, e_ops = [sigmaz()])
println(sol.expect)

Code Output

QuantumObject{KetQuantumObject, Dimensions{1, Tuple{Space}}, Vector{ComplexF64}}[
Quantum Object:   type=Ket   dims=[2]   size=(2,)
2-element Vector{ComplexF64}:
 1.0 + 0.0im
 0.0 + 0.0im]

ComplexF64[1.0 + 0.0im 6.93949973204724e-310 + 6.93949973206147e-310im]

Expected Behaviour

QuantumObject{KetQuantumObject, Dimensions{1, Tuple{Space}}, Vector{ComplexF64}}[
Quantum Object:   type=Ket   dims=[2]   size=(2,)
2-element Vector{ComplexF64}:
 1.0 + 0.0im
 0.0 + 0.0im, 
Quantum Object:   type=Ket   dims=[2]   size=(2,)
2-element Vector{ComplexF64}:
 1.0 + 0.0im
 0.0 + 0.0im]

ComplexF64[1.0 + 0.0im 1.0 + 0.0im]

Your Environment

Julia              Ver. 1.10.5
QuantumToolbox     Ver. 0.25.0
SciMLOperators     Ver. 0.3.12
LinearSolve        Ver. 2.38.0
OrdinaryDiffEqCore Ver. 1.12.1

Additional Context

No response

[albertomercurio]

I think this is related to how DifferentialEquations.jl handles tstops. I will make a PR by just raising an error if tlist contains repeated values.

[ytdHuang]

I think this is related to how DifferentialEquations.jl handles tstops. I will make a PR by just raising an error if tlist contains repeated values.

Yeah, cause it works if we specify tlist = [0, 1e-100]