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The following article was originally published in 2015, but it's so fascinating, here it is again:
Can the past be changed by the FUTURE? Bizarre quantum experiment by Professor Kater Murch suggests time can run backwards
The theory follows another postulated by scientists back in December 2014.
They proposed that at the moment of the Big Bang (illustrated), a 'mirror universe' to our own was created that moves in the opposite direction through time - and intelligent beings in each one would perceive the other to be moving backwards
Scientists in the US have devised a series of new experiments to probe the quantum mechanical properties of single particles.
These particle have a state that is not merely unknown, but totally undefined before it is measured.
The act of measurement itself that forces the particle to collapse to a definite state - as evidenced in the infamous Schrödinger's cat thought experiment.
Professor Kater Murch at Washington University has found that by knowing the future outcome of a particle, its state in the past altered. Without knowing the information, the state is more likely to remain the same. In other words, knowing future events can change the past.
If this proves true in our 'classical' world, it would mean that what we're doing now has been influenced by the decision made by a future version of us.
This all remains theory, but physicists have created devices that allowed them to measure these fragile quantum systems to see if this really is the case in the quantum world.
SCHRODINGER'S CAT EXPERIMENT
- Schrödinger's cat is a thought experiment created by Austrian physicist Erwin Schrödinger in 1935.
- In the hypothetical experiment a cat is placed in a sealed box next to a radioactive sample, a Geiger counter and a bottle of poison.
- If the Geiger counter detects that the radioactive material has decayed, it will trigger the smashing of the bottle of poison and the cat will be killed.
- The experiment was designed to show the flaws in something known as the ‘Copenhagen interpretation’ of quantum mechanics.
- This states that a particle exists in all states at once until observed.
- If the Copenhagen interpretation suggests the radioactive material can have simultaneously decayed and not decayed in the sealed environment, then it follows the cat too is both alive and dead until the box is opened.
(Blogger's note: The quantum cat story has been retold for many decades. But the choice of an animal was wrong to begin with. What about the experiment from the cat's perspective? He has a consciousness too. That complicates things. This concept would be easier to understand if they had chosen an inanimate object as being either intact or destroyed.)
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| Prof. Kater Murch |
Professor Kater Murch at Washington University in St. Louis used this technique to look at the quantum state of two particles at different stages in their evolution.
The quantum state was detected by putting a circuit inside a microwave box.
A few microwave photons – or particles of light – were sent into the box, where their quantum fields interacted with the circuit. When the photons exited the box they had information about the quantum system.
'We start each run by putting the qubit in a superposition of the two states,' Professor Murch said. 'Then we do a strong measurement but hide the result, continuing to follow the system with weak measurements.'
They then try to guess the hidden result, which is their version of the missing page of the murder mystery. 'Calculating forward, the probability of finding the system in a particular state, your odds of guessing right are only 50-50,' Murch said.
'But you can also calculate backward using something called an effect matrix. Just take all the equations and flip them around. They still work and you can just run the trajectory backward.
'So there's a backward-going trajectory and a forward-going trajectory and if we look at them both together and weight the information in both equally, we get something we call a hindsight prediction, or 'retrodiction.'
The shattering thing about the retrodiction is that it is 90 per cent accurate.
The shattering thing about the retrodiction is that it is 90 per cent accurate.
When the physicists check it against the stored measurement of the system's earlier state it is right nine times out of 10.
This suggests that in the quantum world time runs both backward and forward whereas in the classical world it only runs forward.
Professor Murch told Dailymail.com that it's as if you left your keys somewhere in the house, but couldn't remember where. In the quantum world, they could exist in every room of the house simultaneously.
When you eventually find them in the kitchen, in the classical world it is clear that they were there all along, in the quantum world the uncertainty is intrinsic, but Profesor Murch was able to show that indeed hindsight can be applied to make a better guess about where they were in the past.
In the same way, the improved odds in the current experiment imply the measured quantum state somehow incorporates information from the future as well as the past.
And that might implies that time, notoriously an arrow in the classical world, is a double-headed arrow in the quantum world.
'It's not clear why in the real world, the world made up of many particles, time only goes forward and entropy always increases,' Professor Murch added.
'But many people are working on that problem and I expect it will be solved in a few years,' he said.
Source
http://www.dailymail.co.uk/sciencetech/article-2946445/Can-past-changed-FUTURE-Bizarre-quantum-experiment-suggests-time-run-backwards.html
Journal Reference:
- D. Tan, S. Weber, I. Siddiqi, K. Mølmer, K. W. Murch. Prediction and retrodiction for a continuously monitored superconducting qubit. Physical Review Letters, 2015 [link]
http://www.sciencedaily.com/releases/2015/02/150209083011.htm
Photo of Prof. Murch
Credit: Joe Angeles/WUSTL Photos
via Science Daily
RELATED
Very cool video produced by New Scientist in January 2013
It successfully uses cartoons to explain one of the most difficult concepts in particle physics.
It's only 1.40 minute long and mindboggling in its implications.
Don't miss it.
HOW YOU CAN CHANGE THE PAST
It originally appeared with this short article
More New Scientist videos
ON THIS BLOG:
QUANTUM TRAVEL TO THE PAST? -
SCIENTISTS MOVE PHOTONS THROUGH TIME
 |
| Wormhole - Mark Garlick , Corbis |
Could time travel soon become a reality? Physicists simulate sending quantum light particles to the past for the first time
- University of Queensland researchers say photons can move through time
- A simulation of two wormhole-travelling photons found they could interact
- This suggests, at the smallest scales, jumping through time is possible
- The experiment could solve some famous theories that 'prevent' time travel
- But whether this will be possible on a larger scale remains to be seen
Read more
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