A variant of Planck's constant symbol commonly used in quantum mechanics and theoretical physics calculations.
Examples
Reduced Planck constant (h-bar) in quantum mechanics
E = \hslash\omega
Heisenberg uncertainty principle
\Delta x \Delta p \geq \frac{\hslash}{2}
Schrödinger equation
i\hslash\frac{\partial}{\partial t}\Psi = \hat{H}\Psi