(q, v) = (zeros(N),zeros(N))
𝚯₀(sampler, Δt, q,v)
𝒞 = sampler.𝒞
𝒞_squrt = 𝒞^0.5
for i=1:500
    println(i)
    (q, v̂) = 𝚯₀(sampler, Δt, q,v)
    (q, v) = next_iterate(DΨ, Ψ, 𝒞, 𝒞_squrt, Δt, q, v̂)
end