In 1927, British plumian professor of astronomy at the University of Cambridge, Arthur Stanley Eddington, developed the concept of time’s arrow, which he sought to use to better explicate the asymmetry or mono-directionality of time.
One year later, in 1928, Eddington described the concept in his book, The Nature of the Physical World,
“Let us draw an arrow arbitrarily. If as we follow the arrow we find more and more of the random element in the state of the world, then the arrow is pointing towards the future; if the random element decreases the arrow points towards the past. That is the only distinction known to physics. This follows at once if our fundamental contention is admitted that the introduction of randomness is the only thing which cannot be undone. I shall use the phrase ‘time’s arrow’ to express this one-way property of time which has no analogue in space.”
Researchers led by the U.S. Department of Energy’s (DOE) Argonne National Laboratory were, however, able to reverse Eddington’s “one-way property,” through the utilization of a cloud-accessible IBM 4-qubit quantum computer and send a simulated elementary particle back in time 1/1,000,000th of a second. Given that the researchers were working within the confines of a simulation, they obviously did not send a real particle back in time, rather, the computer mapped the dispersal and reversal of a wave.
The authors clarify the process:
“Here we show that, while in nature the complex conjugation needed for time reversal is exponentially improbable, one can design a quantum algorithm that includes complex conjugation and thus reverses a given quantum state. Using this algorithm on an IBM quantum computer enables us to experimentally demonstrate a backward time dynamics for an electron scattered on a two-level impurity.” (G. B. Lesovik, I. A. Sadovskyy, M. V. Suslov, A. V. Lebedev, & V. M. Vinokur, 2019)
This is to say, the qubits were set to function as particles which were then transformed into a wave and then they discerned a function by which the dispersal of the wave could be reversed, thereby violating the ‘simulated’ laws of physics.
Dr. Jerry Chow, Senior Manager of IBM Q Technology, remarked on the program:
“This particular research fits a category of known research that proves you can reverse operations in quantum mechanics…”
Whilst the researchers themselves waxed ambivalent on the practical, real world possibility of time reversal, it seems, at present, theoretically plausible. Whilst popular consciousness turns immediately to thoughts of time travel, in considerations of potential practical applications of time reversal, my own thoughts moved in less flashy directions.
Given that the IBM experiment reversed the flow of time one particle-wave at a time, the effects of this process on a macro level object could prove fatal for a carbon based lifeform, as, unless there was profound sychronicity of particle reversal, one could expect subatomic shredding of the test subject (depending, of course, on the scale of the reversal process). In light of these considerations, a better initial use for time reversal technology would be in space defense. Though asteroid-to-earth impacts are rare, they are regular (along cosmic, not civilizational, timescales). According to Robert Marcus, H. Jay Melosh & Gareth Collins, one asteroid the size of 99942 Apophis (370-meters in diameter) will impact the earth once every 80,000 years. It should also be noted that a asteroid does not have to directly impact earth to pose a threat to human settlements; for example, Apophis is predicted to pass 19,400 miles (31,200 kilometres) from earth, April 13, 2029; no direct impact will be made, but there is potential for indirect impact if a chuck of the object breaks off and makes it through the atmosphere. Further, the deeper our species presses into space, the greater the threat of asteroid impact, thus, space detection and defense systems are indispensable and will become only more so. Thus, if a sufficiently large apparatus generating time reversal fields could be strategically deployed, then, theoretically, future civilizations would be able to loop asteroids by throwing them back in time to just before contact with the field whereupon they would promptly re-strike the field, engendering object-stasis so long as the theoretical apparatus remained properly maintained. If the reversal process proves uneven, such that whole object transition is (then-yet) impossible, then it can still be used to tear a potentially threatening asteroid to pieces by ‘punching’ backward holes in the hazardous object thereby stretching it out along its owner previous trajectory (the arrow’s wake) and thus leaving the portion of the asteroid still tumbling along with our arrow, significantly degraded in mass and momentum so as to be rendered harmless to human habitation.
- A. S. Eddington. (1928) The Nature of the Physical World. NY; The Macmillan Company.
- Dennis Overbye. (2019) For a Split Second, a Quantum Computer Made History Go Backward. The New York Times.
- G. B. Lesovik et al. (2019) Arrow of time and its reversal on the IBM quantum computer. Nautre.
- Robert Marcus; H. Jay Melosh & Gareth Collins. (2010) Earth Impact Effects Program. Imperial College London / Purdue University.
- Tristan Greene. (2019) See you earlier: Physicists sent a (simulated) particle back in time. The Next Web.