Time and Entropy in Physics
The relationship between time and entropy
Time is closely linked to entropy, which represents the progression from order to disorder in the universe. Entropy is one of the few elements of physical science that provides a directionality (arrow) to time, requiring a specific direction of time. Entropy flow and creation are linked to change, and based on this understanding, time can be viewed as a kind of “emergent phenomenon” created by the flow of entropy.
Recent research has confirmed that the law of entropy also applies to quantum systems. Mathematically speaking, the entropy of a quantum system always remains the same, but a team of researchers from the Technical University of Vienna (TU Wien) has delved deeper into this apparent contradiction, suggesting that there may be a directionality to time even in quantum mechanics.
Subjectivity and variability in time perception
Human perception of time is inherently subjective and variable. We experience a wide range of time scales, from seconds to decades. Emotions in particular have a strong influence on time perception, and research suggests that motivational orientation, rather than emotional arousal or sentimentality, drives changes in time perception.
Furthermore, time perception is part of the human experience and is essential for daily behavior and personal survival. William James (1890) referred to it as “the stream of consciousness” and emphasized time perception as a central element of consciousness.
Quantum mechanics and nonlinear time
Nonlinear time is also being studied in quantum mechanics. A recent MIT experiment using quantum “time reversal” studied the phenomenon of quantum entangled atoms behaving as if time were flowing backwards.
And on IBM’s quantum computer, researchers succeeded in reversing the flow of time, a result published in March 2019 in the journal Scientific Reports. This opens up new pathways to explore the reverse flow of time in quantum systems.
Physical laws and the directionality of time
Many fundamental physical laws are indifferent to the direction of time and do not contain terms that point to the direction of time. At the microscopic level, the laws of physics are symmetric about time, meaning they behave the same whether time is flowing forward or backward.
However, recent research has found that time can flow in both directions, and it is one of the great mysteries of physics that the fundamental laws of nature do not reflect the difference between moving forward and moving backward.
Einstein’s theory of relativity and spacetime
Albert Einstein’s theory of relativity revolutionized our understanding of time and space. Special relativity determined that the laws of physics are the same for an unaccelerated observer, and showed that the speed of light in a vacuum is the same regardless of how fast the observer is traveling. As a result, he discovered that space and time are intertwined into a single continuum called space-time.
General relativity explains that objects with large masses distort the fabric of space and time, and that this distortion manifests as gravity. Einstein explained that the rotation of a heavy object, such as the Earth, twists and distorts the spacetime around it. NASA’s Gravity Probe B (GP-B) experiment confirmed these theories, finding that the satellite’s precisely calibrated gyroscope axis shifted very slightly over time.
Non-equilibrium thermodynamics and the nature of time
Non-equilibrium thermodynamics was developed by Ilya Prigogine (Nobel Prize winner in 1977) and is a theory that can explain the complexity and dynamics of the world on a cosmic scale and on plant, animal, and human scales. The main difference between equilibrium thermodynamics and its second law is that while entropy increases on a cosmic scale, when looking at local, open systems with supercritical energy inputs, entropy cannot continue to increase indefinitely.
Dr. Bernhard Wesling has proposed a new hypothesis about the nature of time, arguing that “time is created by the flow of entropy.” According to him, the production or export of entropy in an open system leads to the flow of entropy through three-dimensional space, which forms the fourth dimension of space-time, time. The time we measure is proportional to the entropy production, or entropy flow.
The relationship between emotions and time perception
Research by psychologists has shown that emotions have a significant impact on our perception of how time flows. Mihaly Csikszentmihalyi was the first to identify how pleasant experiences affect time perception through the “flow” state. Flow is the experience of being so blissfully immersed in an activity that all distractions are blocked, and a key characteristic of this experience is a distorted sense of time - the feeling that time has passed faster than usual.
And emotions like fear are the most intensively studied emotions when it comes to judging time. Neuroscientist and author David Eagleman had participants in an experiment wear chronological devices and experience a 15-story drop at an amusement park. When questioned later, most people estimated the time of the fall to be longer than it actually was.
A new perspective on nonlinear quantum mechanics
The study of nonlinear quantum mechanics provides new insights into the concept of time. There are four reasons why our current knowledge and understanding of quantum mechanics can be considered incomplete:
- The linear superposition principle has not been experimentally verified for positional eigenstates of objects with more than a thousand atoms.
- There is no universally agreed upon description of the process of quantum measurement.
- There is no universally agreed explanation for the observed fact that macroscopic objects are not found in superpositions of positional eigenstates.
- Most importantly, the concept of time is classical and therefore external to quantum mechanics: An equivalent reformulation of the theory that does not refer to external classical time must exist.
Researchers argue that this reformulation is an extreme case of nonlinear quantum theory, where nonlinearities become important at the Planck mass scale. These nonlinearities may provide insight into the problems mentioned above.
The relationship between time measurement and entropy
Research has shown that accurate measurement of time increases the entropy of the universe. Clocks with controllable accuracy have shown that the more accurate a clock is at measuring time, the more entropy it produces in the form of heat, suggesting that time measurement itself is a physical process and is directly related to the increase in entropy.