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{{Short description|Quantum Collection topic on Quantum revival}}
{{Quantum book backlink|Quantum dynamics and evolution}}
{{Quantum book backlink|Quantum dynamics and evolution}}
{{Quantum article nav|previous=Physics:Quantum speed limit|previous label=Speed limit|next=Physics:Quantum reflection|next label=Reflection}}
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[[File:Fullrevival.gif|thumb|right|Full and exact revival of the semi-Gaussian wave function in an infinite two-dimensional [[infinite potential well|potential well]] during its time evolution. In between the fractional revivals occur when the scaled shape of the wave function replicates itself integer number of times over the well area.]]
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In [[Physics:Quantum mechanics|quantum mechanics]], the '''quantum revival'''<ref>
__TOC__
{{cite journal
</div>
|author1=J.H. Eberly |author2=N.B. Narozhny |author3=J.J. Sanchez-Mondragon  |name-list-style=amp | year        = 1980
| title      = Periodic spontaneous collapse and revival in a simple quantum model
| journal    = Phys. Rev. Lett.
| volume      = 44
| issue      = 20
| pages      = 1323–1326
| doi        = 10.1103/PhysRevLett.44.1323
| bibcode=1980PhRvL..44.1323E
}}
</ref>
is a periodic recurrence of the quantum [[Wave function|wave function]]
from its original form during the time evolution either many times in space as the multiple scaled fractions
in the form of the initial wave function (fractional revival) or approximately or exactly to its original
form from the beginning (full revival). The quantum wave function periodic in time exhibits therefore the full revival
every period. The phenomenon of revivals is most readily observable for the wave functions being [[Physics:Trojan wave packet|well localized]] [[Physics:Wave packet|wave packet]]s at the beginning of the time evolution for example in the hydrogen atom. For Hydrogen, the fractional revivals show up
as multiple angular Gaussian bumps around the circle drawn by the radial maximum of leading [[Physics:Hydrogen atom|circular state]] component (that with the highest amplitude in the eigenstate expansion)  of the
original localized state  and the full revival as the original Gaussian.<ref>
{{cite journal
|author1=Z. Dacic Gaeta  |author2=C. R. Stroud, Jr.
|name-list-style=amp | year        = 1990
| title      = Classical and quantum mechanical dynamics of quasiclassical state of a hydrogen atom
| journal    = Phys. Rev. A
| volume      = 42
| issue      = 11
| pages      = 6308–6313
| doi        = 10.1103/PhysRevA.42.6308
|pmid=9903927
| bibcode=1990PhRvA..42.6308G
}}
</ref>
The full revivals are exact for the infinite quantum well, [[Physics:Quantum harmonic oscillator|harmonic oscillator]] or the [[Physics:Hydrogen atom|hydrogen atom]], while for shorter times are approximate
for the hydrogen atom and a lot of quantum systems.<ref>{{cite journal |title= Nonsmooth and level-resolved dynamics illustrated with a periodically driven tight binding model |year=2014 |last1=Zhang |first1=Jiang-Min |last2=Haque |first2=Masudul |journal=Scienceopen Research |doi=10.14293/S2199-1006.1.SOR-PHYS.A2CEM4.v1 |arxiv = 1404.4280|s2cid=57487218 |doi-access=free }}</ref>


[[File:ColRev3da10.tif|ColRev3a10|left|500px]]
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'''Quantum revival''' is the reappearance of an initially localized quantum wave packet after it has spread and evolved for a characteristic time. The effect occurs because the phases of the energy eigenstate components can realign, causing the probability distribution to resemble its earlier form.


The plot of  collapses and revivals of quantum oscillations of the JCM atomic inversion.<ref>{{cite journal|author1=A. A. Karatsuba |author2=E. A. Karatsuba | title=  A resummation formula for collapse and revival in the Jaynes–Cummings model| pages=195304, 16| journal= J. Phys. A: Math. Theor.| volume= 42| year= 2009|issue=19 | doi= 10.1088/1751-8113/42/19/195304|bibcode = 2009JPhA...42s5304K |s2cid=120269208 }}</ref>
Revivals are especially clear in systems with discrete, nonlinear energy spectra, such as particles in idealized wells, Rydberg atoms, molecular wave packets, and other bound quantum systems. Fractional revivals can occur at intermediate times, when the wave packet splits into several smaller copies. The phenomenon links wave-packet dynamics, interference, semiclassical motion, and the spectral structure of quantum systems.
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[[File:Fullrevival.gif|thumb|280px|Quantum revival.]]
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==Example - arbitrary truncated wave function of the quantum system with rational energies==
==Example - arbitrary truncated wave function of the quantum system with rational energies==
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:<math>H \psi_i = E_i \psi_i</math>
:<math>H \psi_i = E_i \psi_i</math>


and let the energies  be the [[Rational number|rational]] fractions of some constant <math>C</math>
and let the energies  be the rational fractions of some constant <math>C</math>


:<math>E_i= C {M_i \over N_i}</math>
:<math>E_i= C {M_i \over N_i}</math>


(for example for [[Physics:Hydrogen atom|hydrogen atom]] <math>M_i=1</math>, <math>N_i=i^2</math>, <math>C=-13.6 eV</math>.
(for example for [[Physics:Quantum atoms/hydrogen|hydrogen atom]] <math>M_i=1</math>, <math>N_i=i^2</math>, <math>C=-13.6 eV</math>.


Then the truncated (till <math>\mathbb{N}_{max}</math> of states)  solution of the time dependent Schrödinger equation is
Then the truncated (till <math>\mathbb{N}_{max}</math> of states)  solution of the time dependent Schrödinger equation is
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the exact spectrum in resonance around the average number of photons <math>n_0=100</math> is approximated by the polynomial in the photon quantum number <math>n</math> <math>E(n)=a \delta n^2 + b \delta n + c</math>, <math>\delta n = n - n_0</math>]].
the exact spectrum in resonance around the average number of photons <math>n_0=100</math> is approximated by the polynomial in the photon quantum number <math>n</math> <math>E(n)=a \delta n^2 + b \delta n + c</math>, <math>\delta n = n - n_0</math>]].


Let <math>L_{cm}</math>  be to lowest common multiple of all <math>N_i</math> and <math>L_{cd}</math> [[Greatest common divisor|greatest common divisor]] of all <math>M_i</math>
Let <math>L_{cm}</math>  be to lowest common multiple of all <math>N_i</math> and <math>L_{cd}</math> greatest common divisor of all <math>M_i</math>
then for each <math>N_i</math> the <math>{L_{cm}}/ N_i</math> is an integer, for each <math>M_i</math> the <math>{M_{i}}/ L_{cd}</math> is an integer, <math>2 \pi M_i {L_{cm}}/(N_i L_{cd})</math> is the full multiple  of <math>2 \pi</math> angle and
then for each <math>N_i</math> the <math>{L_{cm}}/ N_i</math> is an integer, for each <math>M_i</math> the <math>{M_{i}}/ L_{cd}</math> is an integer, <math>2 \pi M_i {L_{cm}}/(N_i L_{cd})</math> is the full multiple  of <math>2 \pi</math> angle and


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:<math>T={2 \pi \hbar \over {L_{cd} C}} L_{cm}</math>.
:<math>T={2 \pi \hbar \over {L_{cd} C}} L_{cm}</math>.


For the quantum system as small as Hydrogen and <math>\mathbb{N}_{max}</math> as small as 100 it may take quadrillions of  years till it will fully revive. Especially once created by fields the [[Physics:Trojan wave packet|Trojan wave packet]] in a
For the quantum system as small as Hydrogen and <math>\mathbb{N}_{max}</math> as small as 100 it may take quadrillions of  years till it will fully revive. Especially once created by fields the Trojan wave packet in a
hydrogen atom exists without any external fields
hydrogen atom exists without any external fields
[[Physics:Stroboscopic effect|stroboscopically]] and eternally repeating itself  
stroboscopically and eternally repeating itself  
after sweeping almost the whole hypercube of quantum phases exactly every full revival time.
after sweeping almost the whole hypercube of quantum phases exactly every full revival time.


The striking consequence is that no finite-bit computer can propagate the numerical wave function accurately for the arbitrarily long  
The striking consequence is that no finite-bit computer can propagate the numerical wave function accurately for the arbitrarily long  
time. If the processor number is n-[[Bit|bit]] long  floating point number then the number can be stored by the computer only with the finite accuracy after the comma and the energy is (up to 8 digits after the comma)  for example 2.34576893 = 234576893/100000000 and as the finite fraction it
time. If the processor number is n-bit long  floating point number then the number can be stored by the computer only with the finite accuracy after the comma and the energy is (up to 8 digits after the comma)  for example 2.34576893 = 234576893/100000000 and as the finite fraction it
is exactly rational and the full revival occurs for any wave function of any quantum system  after the time <math>t/2 \pi=100000000</math> which is its maximum exponent and so on that may not be true for all quantum systems or all stationary quantum systems undergo the full and exact revival numerically.
is exactly rational and the full revival occurs for any wave function of any quantum system  after the time <math>t/2 \pi=100000000</math> which is its maximum exponent and so on that may not be true for all quantum systems or all stationary quantum systems undergo the full and exact revival numerically.


In the system with the rational energies i.e. where the quantum exact full revival exists its existence immediately proves the quantum [[Poincaré recurrence theorem]] and the time of the full quantum revival equals to the Poincaré recurrence time.  
In the system with the rational energies i.e. where the quantum exact full revival exists its existence immediately proves the quantum Poincaré recurrence theorem and the time of the full quantum revival equals to the Poincaré recurrence time.  
While the rational numbers are [[Dense set|dense]] in real numbers and the arbitrary function of  
While the rational numbers are dense in real numbers and the arbitrary function of  
the quantum number can be approximated arbitrarily exactly with Padé approximants with the  
the quantum number can be approximated arbitrarily exactly with Padé approximants with the  
coefficients of arbitrary decimal precision for the arbitrarily long time each quantum system therefore revives  
coefficients of arbitrary decimal precision for the arbitrarily long time each quantum system therefore revives  
almost exactly. It also means that the Poincaré recurrence and the full revival is mathematically the same thing<ref>{{cite journal |first1=P. |last1=Bocchieri |first2=A. |last2=Loinger |title=Quantum Recurrence Theorem |journal=[[Physics:Physical Review|Phys. Rev.]] |volume=107 |issue=2 |pages=337–338 |year=1957 |doi=10.1103/PhysRev.107.337 |bibcode = 1957PhRv..107..337B }}</ref> and it is  
almost exactly. It also means that the Poincaré recurrence and the full revival is mathematically the same thing<ref>{{cite journal |first1=P. |last1=Bocchieri |first2=A. |last2=Loinger |title=Quantum Recurrence Theorem |journal=Phys. Rev. |volume=107 |issue=2 |pages=337–338 |year=1957 |doi=10.1103/PhysRev.107.337 |bibcode = 1957PhRv..107..337B }}</ref> and it is  
commonly accepted that the recurrence is called the full revival if it occurs after the reasonable and physically measurable time  
commonly accepted that the recurrence is called the full revival if it occurs after the reasonable and physically measurable time  
that is possible to be detected by the realistic apparatus and this happens due to a very special energy spectrum having a large basic energy  
that is possible to be detected by the realistic apparatus and this happens due to a very special energy spectrum having a large basic energy  
spacing gap of which the energies are arbitrary (not necessarily harmonic) multiples.
spacing gap of which the energies are arbitrary (not necessarily harmonic) multiples.


==See also==
== See also ==
* [[Poincaré recurrence theorem]]
{{#invoke:PhysicsQC|tocHeadingAndList|Physics:Quantum basics/See also}}


==References==
==References==
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[[Category:Quantum chaos theory]]
[[Category:Quantum chaos theory]]


{{Sourceattribution|Quantum revival}}
{{Author|Harold Foppele}}
 
{{Sourceattribution|Physics:Quantum revival|1}}

Latest revision as of 22:26, 23 May 2026

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Quantum revival is the reappearance of an initially localized quantum wave packet after it has spread and evolved for a characteristic time. The effect occurs because the phases of the energy eigenstate components can realign, causing the probability distribution to resemble its earlier form.

Revivals are especially clear in systems with discrete, nonlinear energy spectra, such as particles in idealized wells, Rydberg atoms, molecular wave packets, and other bound quantum systems. Fractional revivals can occur at intermediate times, when the wave packet splits into several smaller copies. The phenomenon links wave-packet dynamics, interference, semiclassical motion, and the spectral structure of quantum systems.

Quantum revival.

Example - arbitrary truncated wave function of the quantum system with rational energies

Consider a quantum system with the energies Ei and the eigenstates ψi

Hψi=Eiψi

and let the energies be the rational fractions of some constant C

Ei=CMiNi

(for example for hydrogen atom Mi=1, Ni=i2, C=13.6eV.

Then the truncated (till max of states) solution of the time dependent Schrödinger equation is

Ψ(t)=i=0maxaieiEitψi
Superrevival of the inversion (return of the full approximate revivals to the original shape) in Jaynes-Cummings model when the exact spectrum in resonance around the average number of photons n0=100 is approximated by the polynomial in the photon quantum number n E(n)=aδn2+bδn+c, δn=nn0

.

Let Lcm be to lowest common multiple of all Ni and Lcd greatest common divisor of all Mi then for each Ni the Lcm/Ni is an integer, for each Mi the Mi/Lcd is an integer, 2πMiLcm/(NiLcd) is the full multiple of 2π angle and

Ψ(t)=Ψ(t+T)

after the full revival time time

T=2πLcdCLcm.

For the quantum system as small as Hydrogen and max as small as 100 it may take quadrillions of years till it will fully revive. Especially once created by fields the Trojan wave packet in a hydrogen atom exists without any external fields stroboscopically and eternally repeating itself after sweeping almost the whole hypercube of quantum phases exactly every full revival time.

The striking consequence is that no finite-bit computer can propagate the numerical wave function accurately for the arbitrarily long time. If the processor number is n-bit long floating point number then the number can be stored by the computer only with the finite accuracy after the comma and the energy is (up to 8 digits after the comma) for example 2.34576893 = 234576893/100000000 and as the finite fraction it is exactly rational and the full revival occurs for any wave function of any quantum system after the time t/2π=100000000 which is its maximum exponent and so on that may not be true for all quantum systems or all stationary quantum systems undergo the full and exact revival numerically.

In the system with the rational energies i.e. where the quantum exact full revival exists its existence immediately proves the quantum Poincaré recurrence theorem and the time of the full quantum revival equals to the Poincaré recurrence time. While the rational numbers are dense in real numbers and the arbitrary function of the quantum number can be approximated arbitrarily exactly with Padé approximants with the coefficients of arbitrary decimal precision for the arbitrarily long time each quantum system therefore revives almost exactly. It also means that the Poincaré recurrence and the full revival is mathematically the same thing[1] and it is commonly accepted that the recurrence is called the full revival if it occurs after the reasonable and physically measurable time that is possible to be detected by the realistic apparatus and this happens due to a very special energy spectrum having a large basic energy spacing gap of which the energies are arbitrary (not necessarily harmonic) multiples.

See also

Table of contents (217 articles)

Index

Full contents

References

  1. Bocchieri, P.; Loinger, A. (1957). "Quantum Recurrence Theorem". Phys. Rev. 107 (2): 337–338. doi:10.1103/PhysRev.107.337. Bibcode: 1957PhRv..107..337B. 


Author: Harold Foppele


Source attribution: Physics:Quantum revival