The factorisation method for constructing eigenstates and eigenvalues of the Schrodinger equation, based on the algebra of supersymmetry, is applied to second-order relativistic equations such as ...

These observances are a visible reminder of collective remembrance, sacrifice and gratitude. Lowering the U.S. or state flags to half-staff is a longstanding tradition that signifies public mourning ...

The Stars and Stripes will fly at half-staff across two states in America today after a nationwide alert over the weekend to honor those killed in the Pearl Harbor bombings. Today, the state flags of ...