High School When was the first double slit experiment done using a detector?

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The discussion centers on the impact of particle detectors on the interference pattern in double slit experiments, highlighting that early experiments like the Fresnel-Arago utilized polarized light before quantum mechanics was established. It emphasizes that significant double slit experiments demonstrate interference patterns only when both slits are open and no path information is available, which defies classical physics explanations. The conversation also touches on the idea of external influences, such as Earth's magnetic field, potentially affecting particle trajectories, but concludes that these factors do not account for the unique quantum behavior observed. Overall, the interference pattern's emergence from individual particles remains a fundamental aspect of quantum mechanics. The thread underscores the distinction between classical and quantum interpretations of such experiments.
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When was it first experimentally seen that particle detectors can change the interference pattern effect expected in a double slit experiment? Is it still theoretical?

What were some double slit experiments in the early era of quantum mechanics? How were they handled?
 
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aceleratio said:
When was it first experimentally seen that particle detectors can change the interference pattern effect expected in a double slit experiment? Is it still theoretical?
The first experimental demonstration was probably the Fresnel-Arago experiments with polarized light. These preceded the development of quantum mechanics by about a century, so of course no one at the time realized that that's what they had done. At the other extreme, this experiment is a well-executed modern example.

Do remember, however, that if you're trying to distinguish classical physics from quantum physics the most important double-slit experiments are the ones in which both slits are open, there are no detectors providing which path information, particles are sent towards the slits one at a time, and the interference pattern builds up over time, one particle impact at a time. There is simply no classical explanation for this phenomenon, while conversely there's nothing especially surprising about not getting an interference pattern.
 
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Hi Nugatory, good info,

Nugatory said:
There is simply no classical explanation for this phenomenon, while conversely there's nothing especially surprising about not getting an interference pattern.

I have long wondered whether there is any specific reason that we can exclude the possibility of the interference pattern being caused by streaming with waves or vibrations in the Earth's magnetic field, and that outside of these influences the trajectories might be straight?

Twin Slits In A Farriday Cage!
Almost a great sounding movie, but is it an experiment worth considering in order to eliminate any influence from electromagnetic "weather"?
 
RelativeRelativity said:
...outside of these influences the trajectories might be straight?
I don't see how any amount of influencing trajectories can lead to a classical explanation of how an interference pattern builds up one particle at a time when two slits are open but not when only one slit is open.
 
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Of course, thank you most kindly :)
 
Time reversal invariant Hamiltonians must satisfy ##[H,\Theta]=0## where ##\Theta## is time reversal operator. However, in some texts (for example see Many-body Quantum Theory in Condensed Matter Physics an introduction, HENRIK BRUUS and KARSTEN FLENSBERG, Corrected version: 14 January 2016, section 7.1.4) the time reversal invariant condition is introduced as ##H=H^*##. How these two conditions are identical?

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