Free-particle propagator
= Free-particle propagator
For a free particle of mass $m$ on the line,
$$
K(x_f,T;x_i,0)=\sqrt{\frac{m}{2\pi i\hbar T}}
\exp\!\left(\frac{im(x_f-x_i)^2}{2\hbar T}\right).
$$
= Free-particle propagator
For a free particle of mass $m$ on the line,
$$
K(x_f,T;x_i,0)=\sqrt{\frac{m}{2\pi i\hbar T}}
\exp\!\left(\frac{im(x_f-x_i)^2}{2\hbar T}\right).
$$