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Can someone please explain wave particle duality for large bodies? Why don't large bodies exhibit wave like nature for example if I am walking with some momentum, the wavelength associated with me is $h/p$ what does this mean?

Qmechanic
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Sasmit Vaidya
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1 Answers1

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de Broglie wave length is defined as : $$\lambda _{B}={\frac {h}{p}}$$ So if for example your mass is 60 kg and you are moving with a sports car with a speed of 200 km/h, then your de Broglie wave-length would be on the order of $10^{-37}$m. No physical length can be smaller than Plank length which is $1.616\;229\times 10^{-35}\ \mathrm {m}$. Thus de Broglie wave lengths for macroscopic big objects means nothing.

Agnius Vasiliauskas
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  • Yes but what when I move a cricket ball slowly I can vary the speed of the cricket ball of I make it let's say 10^-24 then ? – Sasmit Vaidya Sep 05 '19 at 13:56
  • Some distance per second which is smaller or comparable to electron diameter ? Such technology doesn't exists which would let to control macroscopic object speed with microscopic precision comparable to electron diameter. Even if let's say hypothetically you would invent such thing, then according to Heisenberg uncertainty principle setting such high precision on macroscopic body speed in effect will make it's position unknown. So it's NOT doable. – Agnius Vasiliauskas Sep 05 '19 at 15:53
  • Ok what if I am sitting on my table does that not make my momentum zero – Sasmit Vaidya Sep 14 '19 at 06:44
  • Plugin zero momentum into the formula and you will get $\lambda {B} = \infty$ - infinite de Broglie wavelength. If you can't detect wave periodicity in space - then this is not a wave at all. Pretty much like circle with infinite radius is not circle at all. Any system with _infinite parameter value is un-physical and makes no sense. The only exception to this rule is a singularity in black hole center. However this can also mean that as for now simply we don't have good quantum gravity theory which would resolve infinity issues at black hole center – Agnius Vasiliauskas Sep 14 '19 at 08:40