دانلود کتاب پدیده در ماده متراکم و گرانش کوانتومی

The universe is not just a formless blob of particles. It has struc-tures on multiple scales. Why? You might expect vast numbers of particles to behave like vast numbers of particles, far too complex for any mortal mind to grasp. Yet they achieve a collective simplicity. Scientists say higher-level properties “emerge.” Exactly how they do this is still one of the great ques-tions of science. It is not even clear whether emergence merely repackages microscopic physics or adds something genuinely new. Every field of science contributes to the study of emergence. The same principles of organization that govern masses of particles also apply to bird flocks, traffic jams, and national economies. But if any discipline can claim emergence as its central concern, it is condensed-matter physics, which analyzes how material proper-ties flow from fundamental physics. Its practitioners have discovered entirely new forms of collective order involving quantum physics and the special mathematics of topology. Their insights are migrating even into fundamental physics. Theorists studying quantum gravity now think that space and time, once thought the rock-bottom level of reality, are emergent structures from an even deeper one.