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modulus
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I have just started reading about a classical electromagnetic treatment of light-matter interaction (beginning with dispersion relations, and then moving on to the standard phenomena - reflection, refraction, etc.). The discussion begins with a forewarning that light is not 'continuous' as the classical electromagnetic treatment suggests. It touches upon the photonic nature of light, and this has got me confused:
We say that light exhibits its particle nature only when it interacts with matter. But going by what quantum mechanics teaches us, isn't the matter light would interact with a wave (-particle) too?I mean, consider a grain of sand. Apparently, we cannot observe its wave-particle duality because even while sitting still, it always has a certain instantaneous momentum due to thermal vibrations, which give it a corresponding wavelength too less to be observable.
Now, I want to apply 'light-logic' to this grain of sand: when light is not being observed (for example, as it propagates through vacuum) it behaves like a wave (a probability wave) and then collapses into a specific state when observed (i.e., when it interacts with 'matter'). By a similar token, one would suppose a sand particle to be a wave when not interacting with other matter or light, but it is clearly always a particle no matter what...how? I thought maybe it is because it is always interacting with 'ambient' photons, so it is always in a state of 'observation'. But then, the same should have been true for a photon as it moves between the slitted and solid planes in Young's double slit experiment - after all, it is always interacting with the particles in the air isn't it? Does being so small somehow give the photon a special status?Basically, I'm trying to analogically apply the concepts we use with microscopic particles to macroscopic objects, but things don't seem to fit. How am I supposed to imagine the wave (probability wave) of, say, a sand particle (which has vanishing wavelength)?
We say that light exhibits its particle nature only when it interacts with matter. But going by what quantum mechanics teaches us, isn't the matter light would interact with a wave (-particle) too?I mean, consider a grain of sand. Apparently, we cannot observe its wave-particle duality because even while sitting still, it always has a certain instantaneous momentum due to thermal vibrations, which give it a corresponding wavelength too less to be observable.
Now, I want to apply 'light-logic' to this grain of sand: when light is not being observed (for example, as it propagates through vacuum) it behaves like a wave (a probability wave) and then collapses into a specific state when observed (i.e., when it interacts with 'matter'). By a similar token, one would suppose a sand particle to be a wave when not interacting with other matter or light, but it is clearly always a particle no matter what...how? I thought maybe it is because it is always interacting with 'ambient' photons, so it is always in a state of 'observation'. But then, the same should have been true for a photon as it moves between the slitted and solid planes in Young's double slit experiment - after all, it is always interacting with the particles in the air isn't it? Does being so small somehow give the photon a special status?Basically, I'm trying to analogically apply the concepts we use with microscopic particles to macroscopic objects, but things don't seem to fit. How am I supposed to imagine the wave (probability wave) of, say, a sand particle (which has vanishing wavelength)?
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