Questions tagged [emergent-properties]

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Understanding Verlinde: How to get from emergent gravity to MOND

Verlinde ( https://arxiv.org/abs/1611.02269 ) tries to deduce MOND from emergent gravity. Can you help? Emergent or entropic gravity goes back to Jacobson. He starts with the entropy-area connection $...
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Spacetime metric as an order parameter?

I've been reading on Sean Carroll's ideas ([1], [2]) on space from Hilbert space and bulk entanglement gravity in which he tries (and succeds) to derive the linearized Einstein equation directly from ...
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1answer
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Is there an ambiguity in time in the absence of clocks?

Imagine 2 clocks space 2 meters apart with a vacuum in between. These are macroscopic objects with which we can measure time. But in between these, according to general relativity, we can foliate ...
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Dark matter as an emergent phenomenon

Dark matter is invoked as a solution to anomalies in galactic rotation curves, galaxy motions in clusters, and gravitational lensing (please mention other evidence for dark matter that is relevant to ...
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1answer
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Emergence of elastic (as well as plastic) properties of metals

Whenever a force is applied on an metal it causes deformation and a stress is generated. Metals form a lattice which has lower energy than isolated metal atoms (due to the formation of metallic ...
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Hamiltonian mechanics on irregular graphs - application to the physics of intelligence?

Are there physical models that describe mechanical/Hamiltonian dynamics of some particle/subject on irregular graphs? Apparently, the dynamics on the more or less regular lattices can be described ...
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53 views

Why is it sometimes impossible to derive macroscopic properties of a system starting from a microscopic analysis?

I have read Philip Anderson and Robert Laughlin articles about emergence. They claim that a macroscopic description of some systems are sometimes impossible to be derived from a microscopic analysis. ...
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Is friction an emergent phenomenon?

The microscopic origin of the frictional forces is due to contact between irregularities of the surfaces as seen here [1]. Electromagnetic interactions are the fundamental forces responsible for ...
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Do condensed-matter field theories with multiple fields generically have multiple speeds of sound?

It is well known that the low-energy physics of many non-relativistic condensed matter systems can be described by field theories that display emergent Lorentz symmetry. The heuristic way to figure ...
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Are objects repelled by the cosmological horizon in Lambda-CDM cosmology?

When an observer watches a distant object, is there a gravitational influence of the horizon on that object? ("Distant" here is meant to mean: at a distance that is a sizeable fraction of the Hubble ...
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Why do the colloidial particles in a viscuous fluid stop (stroboscopically) moving below a treshold as described in the experiment below?

In a nice experiment (inspired by the renowned physicist G.I. Taylor), which can be seen in this video (around 12 minutes), Professor David Pine and Professor Jerry Gollub filled a Couette cell with a ...
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107 views

Could the graviton be more than one particle?

I guess this amounts to saying that gravity isn't a fundamental force and is, in fact, an emergent phenomenon (as in Erik Verlinde's theory). If gravity can be 'unified' with the other forces surely ...
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Ghost in quantum many body systems

Since we know the gauge theory can be emergent from local tensor product Hilbert space of quantum many body systems, such as solid state or condensed matter, etc. How do we understand the ghosts in ...
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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 ...
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What does it mean that space-time is emergent?

Edward Witten (Institute for Advanced Study in Princeton), Fields medaillist, the discoverer of M-theory and considered a genius by many, recently gave one of his rare interviews (https://www....
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303 views

Are mass, and therefore time, emergent phenomena?

As I understand, massless particles such as gluons and photons do not experience time due to the principles of relativity. An electron isn't sincerely an elementary particle - doesn't it exist more ...
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129 views

Can we tell apart $A$ and $B$? — from a non-relativistic system $A$ to an emergent relativistic system $B$

We know that the non-relativistic system like Graphene with a particular filling of electrons give rise to relativistic Dirac equations at low energy, with multi-flavors of Dirac particles. In terms ...
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66 views

Periodicity of the Kelvin-Helmholtz Instability

Why is the Kelvin-Helmholtz Instability so regular across space? If any perturbations anywhere in the boundary can lead to instability, why doesn't the pattern appear randomly across the boundary? ...
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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 ...
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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 ...
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Property of light [closed]

Is there any type of light wave which can bend like a thread while travelling? Can this light travel without meeting an obstacle?
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How strong could a carbon nanotube be?

I was thinking about the limits of flywheel energy storage and wondered about carbon nanotubes. The amount of energy that can be stored per unit mass in a flywheel depends not on tensile strength but ...
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1answer
170 views

Why does a dynamical gauge field accompany fractionalisation?

I'm trying to understand fractionalisation, of which spin-charge separation is an example. I've read that this is accomplished by introducing a Lagrange multiplier field, which becomes a dynamical ...
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333 views

What are the preferred subsystems of the universe? [closed]

I am not a physicist but I am interested in philosophical implications of theoretical physics. My understanding is that many physical properties like mass, volume, temperature etc. - are emergent ...
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162 views

c “Propagation” in Weber Electrodynamics [closed]

The telegraph model of Weber-Gauss, relying on Weber's electrodynamics, modeled instantaneous action at a distance of the electric scalar potential (Coulomb potential) manifesting as propagation of ...
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1answer
317 views

Can a nondegenerate fermionic topological Mott insulator (TMI) state support an emergent bosonic topological order?

Based on my recent study and motivated by a recent paper, I have a naive question. Consider a 2d Hubbard model for electrons at half filling $H=\sum c_k^\dagger h_k c_k+U\sum n_{i\uparrow }n_{i\...
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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 ...
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2answers
465 views

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 ...
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361 views

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 ...
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320 views

Understanding emergent phenomena in the block universe. (Reworded question)

Each person exists as an unchanging 4D worldtube in the block universe. At each slice of the worldtube there is a present, past and future. However, there is a black box* which appears to exist in ...
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59 views

emergent phenomena from microscopic equations of motion

Is an emergent phenomenon like "superfluidity" or "quantum Hall effect" derivable from microscopic equations of motion? If No, why?
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``What is life?'' by a physicist definition [closed]

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 ...
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287 views

Fractionalization and the structure of spin rotation group?

As we know, the phenomena of fractionalizations in condensed matter physics is fantastic, like fractional spin, fractional charge , fractional statistics, .... And one key point is that the ...
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245 views

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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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“Conceptualizing” neutrinos

Layman here. EE and BS physics. I am "content" in viewing photons/electromagnetic radiation as an "emergent" property of spacetime? due to the electrons ("particles..?") and all their activity jumping ...
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663 views

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'...