The Big 2 ...

Yours truly has always thought the two laws of thermodynamics are the most profound in the multiverse, i.e

The first law: Energy can neither be created nor destroyed; only transformed or transferred from one form to another.

The Second law: The total entropy of an isolated system can never decrease over time.  

Carnot engine diagram (modern) - where an amount of heat QH flows from a high temperature TH furnace through the fluid of the "working body" (working substance) and the remaining heat QC flows into the cold sink TC, thus forcing the working substance to do mechanical work W on the surroundings, via cycles of contractions and expansions.

Seems both laws hold true as they maintain their consistency in the quantum realm at deep level as seen by an exquisite experiment stating that ... physicists have performed an experiment confirming that thermodynamic processes are irreversible in a quantum system—meaning that, even on the quantum level, you can't put a broken egg back into its shell. 

Why this is important.

Irreversibility at the quantum level may seem obvious to most people because it matches our observations of the everyday, macroscopic world. However, it is not as straightforward to physicists because the microscopic laws of physics, such as the Schrödinger equation, are "time-symmetric," or reversible. In theory, forward and backward microscopic processes are indistinguishable.

In reality, however, we only observe forward processes, not reversible ones like broken egg shells being put back together. It's clear that, at the macroscopic level, the laws run counter to what we observe. Now the new study shows that the laws don't match what happens at the quantum level, either.

Seems that the law of initial conditions applies here as well ...

The physicists explain that the answer to this question lies in the choice of the initial conditions. The microscopic laws allow reversible processes only because they begin with "a genuine equilibrium process for which the entropy production vanishes at all times," the scientists write in their paper. Preparing such an ideal initial state in a physical system is extremely complex, and the initial states of all observed processes aren't at "genuine equilibrium," which is why they lead to irreversible processes.

In essence, Absolute Zero is the only way a genuine equilibrium can occur were nothing moves at subatomic level, something that never happens, AFAWK. Awesome is it not? :)