Questions tagged [emergent-properties]
53 questions
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Emergent symmetries
As we know, spontaneous symmetry breaking(SSB) is a very important concept in physics. Loosely speaking, zero temprature SSB says that the Hamiltonian of a quantum system has some symmetry, but the ground state breaks the symmetry.
But what about…
Kai Li
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Phil Anderson's Criticism of Existence of Stable Dissipative Structures
In this book chapter (1987), titled "Broken symmetry, emergent properties, dissipative structures, life," Phil Anderson and Daniel Stein criticize defining life as a dissipative structure (a definition put forward by Prigogine and colleagues) based…
stochastic
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Can renormalization group evolution be used to capture emergence?
I am posing this question with condensed matter systems in mind. Is it, in principle, possible to obtain emergence using the renormalization group (RG)? I read in X.-G. Wen's book (Quantum Field Theory of Many-Body systems) that "we cannot use the…
S.G.
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How to understand the emergent special relativity in the superfluid?
The superfluid vacuum theory was proposed to understand some features of the vacuum (aether) from the emergence point of view. Although made up of non-relativistic atoms, the low-energy excitations of superfluid, i.e. the phonons, are said to be…
Everett You
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How to determine if an emergent gauge theory is deconfined or not?
2+1D lattice gauge theory can emerge in a spin system through fractionalization. Usually if the gauge structure is broken down to $\mathbb{Z}_N$, it is believed that the fractionalized spinons are deconfined. However in general, $\mathbb{Z}_N$ gauge…
Everett You
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18
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Macroscopic laws which haven't been derived from microscopic laws
Can you think of examples where a macroscopic law coexists with a fully known microscopic law, but the former hasn't been derived from the latter (yet)? Or maybe a rule of thumb, which works but hasn't been understood yet. Or some emergence which is…
Gere
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Can anyons emerge from momentum-space other than spatial dimensions?
So far in condensed matter physics, I only know anyons(abelian or nonabelian) can emerge as quasiparticles in 2D real-space.
But is there any possibility to construct anyons in momentum-space ? And what about the braiding, fusion rules in …
Kai Li
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What does it mean that space-time is emergent?
Edward Witten (Institute for Advanced Study in Princeton), Fields medallist, the discoverer of M-theory and considered a genius by many, recently gave one of his rare interviews…
vonjd
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A simple model that exhibits emergent symmetry?
In a previous question Emergent symmetries I asked, Prof.Luboš Motl said that emergent symmetries are never exact. But I wonder whether the following example is an counterexample that has exact emergent spin rotational symmetry.
Just consider the…
Kai Li
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9
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What is the minimal symmetry required for a spin Hamiltonian to describe a spin-liquid ground state?
Let's restrict to the case of spin-1/2 system. As we know, a spin-liquid (SL) state is the ground state of a lattice spin Hamiltonian with no spontaneous broken symmetries (sometime it may spontaneously break time-reversal symmetry and is called a…
Kai Li
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Is the "particle number" of "electrons" well defined in Wen's string-net theory of elementary particles?
According to professor Wen's string-net theory, electrons can be viewed as the elementary excitations of string-net objects. Just like the phonons and magnons are the elementary excitations of crystals and spin systems, respectively.
But as we know,…
Kai Li
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Spin ice / spin liquid v.s. quantum spin ice / quantum spin liquid
What are the distinguishment between (1) spin ice, (2) spin liquid and (3) quantum spin ice, (4) quantum spin liquid?
Apparently the quantum effect for the later (3) and (4) becomes important. But what physical phenomenon of the (1), (2), (3), (4)…
wonderich
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``What is life?'' by a physicist definition
The question is about defining ``What is life?'' in the field of Physics.
Whether there is any (insightful) way of defining ``What is life?'' from physicists.
There are pioneer works, including Erwin Schrödinger's nice book What is life?, cf.…
wonderich
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Emergent Gravity theory by Verlinde
Erik Verlinde has proposed a emergent structure of Gravity in a recent paper Emergent Gravity and the Dark Universe
Abstract from paper cited above
Recent theoretical progress indicates that spacetime and gravity emerge together from the…
Ari
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Is entropy in quantum mechanics emergent or fundamental?
Since a quantum mechanical system, even an isolated system containing one particle, can be described by a density matrix, with entropy for the system given by $\langle S\rangle=-k \rho\ln(\rho)$, is not entropy therefore a property of the system…
user53081
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