This sounds like the old Steady State Theory, which I always thought was thrown out much too quickly when the Big Bang Theory became popular. But such theories need to address the Red Shift, the fact that light from further galaxies is shifted more toward the red, with the amount of shift corresponding to the distance.

The Red Shift has usually been explained as a Doppler effect, meaning that galaxies are moving away from each other, with the speed of recession increasing with distance. This is often referred to as expansion of the universe.

The new theory proposed by Ali and Das suggests that the density of the universe is constant. If galaxies are receding from one another, new matter would have to appear "out of nothing" to maintain a constant density, with new galaxies eventually forming between the receding ones. This continuous creation of new matter, in the form of hydrogen atoms, was actually a key feature of the Steady State Theory, and was one of the arguments that led cosmologists to turn away from it.

Other explanations besides expansion have been proposed for the Red Shift, such as that light "decays" in some manner proportional to distance, but these theories have not acquired much favor.

But in a quantum universe, there would be no problem with new matter appearing, due to fluctuations in the quantum structure of space. It will be interesting to see how the theory proposed by Ali and Das develops. Their paper is highly mathematical and doesn't directly address the red shift question as far as I can see. We will need to see a more complete explanation of its real-world implications.

But I bet they won't dare to call it the New Steady State Theory.