👉 In physics and chemistry, a pseudoscalar is a scalar quantity that has a negative value. In other words, it is a number with a negative sign attached to it. This property makes pseudoscalars important in quantum mechanics and special relativity because they can be used as "coordinates" for the relativistic mass of an object. For example, in classical mechanics, a particle's position (x) can be described by its momentum (p), which is a scalar quantity. However,