Quantum Search for the Origin of Time Reveals No Distinction Between Past and Future

In search of the source of time, University of Surrey physicists Thomas Guff, Chintalpati Umashankar Shastry, and Andrea Rocco examined what they likened to a hot quantum bathtub beneath the endless stretch of eternity.

No matter how hard we try, we can’t remember what will happen tomorrow—and physicists still don’t know why.

They didn’t find what they expected, but instead confirmed that time can flow backward just as easily as it moves forward within the realm of quantum mechanics. Despite this, their findings may eventually help explain why physics insists on the existence of history.

Why Physics Doesn’t Favor the Past or Future

In technical terms, physics is largely symmetrical when it comes to time. While we may never witness an egg uncrack or an oak tree reverse into an acorn, the fundamental laws of most processes offer little guidance on whether an equation should face the past or the future.

There’s no lack of places to search for answers on why the past remains fixed. For instance, cosmologists have studied how the Universe expands from a low to high entropy state. Quantum physicists have considered whether a particle’s growing entanglement with its environment could play a role. However, so far, no clear explanation has emerged for why the dimension of time maintains such cohesion.

Guff, Shastry, and Rocco speculated that quantum equations of motion might contain a mechanism that prevents a system from returning to a past state, acting like a ratchet to ensure the laws of the system don’t move backward.

Modeling Time with Markov Chains

They used a mathematical approximation called a Markov chain to model heated particles in an open container. In this Markovian framework, where the system has no memory beyond the present, each quantum state would depend solely on the immediately preceding state. This could lead to a one-way progression toward the future or an oscillation that might just as easily reverse direction.

Despite thoroughly examining their equations, the team found no indication that time-reversal symmetry conflicted with quantum activity, suggesting that the system’s “memory” showed no preference for the past or future.

“Our findings suggest that while our everyday experience tells us time only moves forward, we are simply unaware that the reverse direction was just as possible,” says Rocco.

Quantum vs. Everyday Time

While time may fluctuate back and forth at the quantum level, it certainly doesn’t behave that way in our everyday world. A real hot bath under the night sky, for instance, will always cool down as heat dissipates into the ever-expanding universe.

The researchers emphasize that their findings do not contradict the laws of thermodynamics. Some physical laws are truly irreversible. However, even if time’s arrow flipped at the quantum level, the system would still cool as expected, implying that thermodynamics doesn’t inherently favor one direction over the other in the quantum realm.

If this holds true, our perception of time as a one-way street may be just one side of a larger picture—mirrored by a second timeline on the other side of the Big Bang, where cosmic expansion and increasing energy unfold from a quantum state that “remembers” the future as easily as the past.

Read the original article on: Science Alert

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