Physics of Stopping Time

Synopsis

This talk examines the popular sci-fi trope of ‘stopping time’ using modern physics. I begin by defining time for different frameworks. Proper time in relativity, unitary time evolution in quantum mechanics/ QFT, and thermodynamic arrow of time associated with entropy increase. Then, I analyze three frameworks for stopping time: (i) a global freeze in which all degrees of freedom stop evolving, (ii) relativistic motion used to make the outside world appear frozen, and (iii) a localized spacetime bubble engineered through time dilation. Simple arguments and order-of-magnitude estimates show that global freeze forbids interactions, the high speed approach requires light speed Lorentz factors and produces lethal effects, and the spacetime bubble demands black hole conditions and extreme( exotic) stress energy. I conclude by discussing subjective time acceleration as an alternative method that shifts the constraints to heat dissipation.