# Does the measurement on a subatomic particle give its mass value?

No doubt I am wondering about the Young's double slit phenomena. If we observe or measure the properties of a subatomic particle, we are able to know its mass, velocity and it comes to existence. So is it true for our natural world? Like we all the form of wave functions and when we interact with an object with our sensors like eye, ear, tongue, touch and smell we give it the shape, mass etc. Otherwise the objects does not exist and form of pure energy.

• Not really. The state of a quantum system can have well defined properties whether observed or not. It is just that the state is uncertain until you observe it. The weirdness of quantum mechanics is that you can never get complete information about what the state was before a measurement, and you can't measure the state without interfering with it irreducibly. Also, we are not special. Any macroscopic system is capable of performing measurements on a quantum system. Feb 20 '13 at 2:37
• The answer to your title question "Does the measurement on a subatomic particle give its mass?" is a simple no. Mass has nothing to do with quantum measurements. Feb 20 '13 at 2:38
• Michael Brown - I put the question in title as I could not put my question really in short sentence. But my real concern is what I asked in the body of the post. Feb 20 '13 at 2:44

If we observe or measure the properties of a subatomic particle, we are able to know its mass,velocity and it comes to existance.

The correct view is we have measured its properties with a given accuracy of measurement. Quantum mechanics tells us that there is an inherent uncertainty in the measurements given by the Heisenberg Uncertainty Principle (HUP).It should be stressed that the HUP deals with the very very small. In our everyday world the indeterminacy it gives can be considered 0.

So is it true for our natural world. Like we all the form of wave functions and when we interact with an object with our sensors like eye,ear,tongue,touch and smell we give it the shape,mass etc.

Yes, all our senses are a type of measurement

Otherwise the objects does not exist and form of pure energy.

This is a philosophical question, how one defines an "object" and the verb "exists".

Macroscopically objects are defined by classical mechanics and the existence of the microcosm does not register in our perceptions, due to the small dimensions where h_bar can be considered practically 0.

The quantum mechanical entities, we call particles, that build up the atoms and molecules and cells from which our everyday reality emerges can be probed with very special experiments. These have shown us that these entities have attributes which collectively we call mass, and energy in the macrocosm, and these are attributed to the microcosm too, but they are found to obey quantum mechanical laws. In the limit of our large dimensions they go back to our classical definitions of energy and mass.

Mass exists and energy exists consistent with our definitions in the microcosm and the quantum mechanical laws.

And one point on "existence" . If you are on a mountain and look to the valley with binoculars,you can see individual houses, cats and dogs and people that you could not see without the binoculars. Without them you saw some indistinguishable blobs. Do dogs and people exists in that village when you look away from the binoculars?

• +1 this: "And one point on "existence" . If you are on a mountain and look to the valley with binoculars,you can see individual houses, cats and dogs and people that you could not see without the binoculars. Without them you saw some indistinguishable blobs. Do dogs and people exists in that village when you look away from the binoculars?" Feb 20 '13 at 6:03