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Fractional revivals of quantum state in tight-binding chain

Quantum Physics · Submitted 4 Mar 2006 · 29 references

Pith's verdict: Real and mostly sound fractional-revival formalism for a discrete chain, but Trev is a factor of 2 too short (wrong small-k dispersion) and the numerics appear to confirm the erroneous model rather than the exact chain.

T0 · AI review

How this review was made: An AI referee (deepseek-v4-flash) read the paper on August 28, 2026 and answered a fixed list of questions about it. T0 is the starting level every paper gets. The levels describe how deeply Pith has checked the paper, never the authors.

  1. T0 AI review An AI read the paper and answered a fixed list of questions.
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  3. T2 Compute The paper's code or calculations re-run with the same results.
  4. T3 Formal statement The claims written out in a formal math language a computer can read.
  5. T4 Proof Those claims proved, and the proof checked by computer.

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arXiv IDquant-ph/0603033 (version 2)
Pith ID2TXPZJDV, Pith's permanent record of this paper and its review
CitationBing Chen, C.P. Sun, Z. Song. "Fractional revivals of quantum state in tight-binding chain." arXiv:quant-ph/0603033 (2006). https://pith.science/paper/2TXPZJDV
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Referee report
The paper

The paper claims

A uniform tight-binding chain splits a Gaussian wave packet into several shape-preserving copies at fractional revival times.

The reading

This paper claims that a Gaussian wave packet on a simple uniform hopping chain, when released at a low-energy site, does not just spread and decay: at times $\tau = p T_{\mathrm{rev}}/q$ it reassembles into several copies of itself, each with the original shape, located at mirror and shifted positions with probability $1/q$ per copy. If the claim holds, quantum information encoded in the packet (for instance its spin) can be routed to one or many receivers by time evolution alone, without engineering the hopping strengths. The result is derived by approximating the band dispersion as quadratic, which makes the lattice behave like the infinite square well, and is checked numerically on a 500-site chain with a packet width of about 24 sites. The paper also introduces a fractional fidelity that stays near 1 whenever the copy at the target site is faithful, even if only a fraction $1/q$ of the amplitude arrives there.

What carries the argument

The engine of the result is the finite Fourier decomposition of the quadratic phase factor, $e^{-ipn^2\pi/q} = \sum_{r=0}^{l-1} b_r e^{-2\pi i nr/l}$, applied to the wave-packet expansion coefficients; the period $l$ is $2q$ for odd $q$ and $q$ for even $q$, and the amplitudes obey $b_r=b_{l-r}$. Feeding this identity are two ingredients: the quadratic dispersion approximation $\varepsilon_k \approx -2J(1-k^2)$, which turns the uniform chain into a discrete version of the infinite square well, and the spectrum-parity matching condition, the condition that energy level spacings and eigenstate parities are both periodic functions of the standing-wave index $n$, which synchronises the phases of the sine standing waves so that the rephasing time is $T_{\mathrm{rev}}$ and the revived pattern appears at the mirror position. The machinery is measured by the mirror fidelity $F(\tau)$ and the fractional fidelity $F_f(\tau)$, the latter dividing out the clone amplitude at the target site.

Extended reading notes

Core claim

At the instant $\tau=pT_{\mathrm{rev}}/q$, with $T_{\mathrm{rev}}=(N+1)^2/(2\pi J)$, an initial Gaussian packet centred at $N_0$ evolves into $l$ sub-packets that closely reproduce the initial profile: one at the mirror position $N_{\mathrm{p}0}=N+1-N_0$, one at the original position $N_0$, and pairs at $N_0\pm 2(N+1)r/l$, where $l=2q$ for odd $q$ and $l=q$ for even $q$, each with probability $|b_r|^2=1/q$. This is the lattice analogue of fractional revivals in the infinite square well, and it follows because the low-energy dispersion is approximately quadratic. For special positions the pattern sharpens: a packet started at $N_0=N/3$ fully revives at its mirror site already at $T_{\mathrm{rev}}/3$, and a superposition of packets at $N/3$ and $2N/3$ revives at $T_{\mathrm{rev}}/24$. Numerically, for a 500-site chain and a packet width of 24 sites, the positions, shapes, and probabilities of the sub-packets match the formula, and the fractional fidelity at the mirror site is close to 1 at many rational times.

Load-bearing premise

The whole clone picture rests on treating the chain's energy spectrum as exactly quadratic for the packet, which is only true for low-energy, broad wave packets; the paper's own Figure 7 shows that when the packet width falls below roughly 24 lattice sites the fractional fidelity drops and the cloned sub-packets lose their shape.

Editorial extensions

If this is right

  • A uniform, unmodulated chain can transfer a qubit encoded in a Gaussian packet from its starting site to the mirror site with unit fidelity at the full revival time, and in one third of that time when the packet starts one third of the way along the chain.
  • Reading out only the clone at the target site gives perfect quantum information transfer at fractional revival times: the fractional fidelity is near 1 whenever that clone is well separated from its neighbours, even though the clone carries only a fraction of the total probability.
  • A superposition of two packets, placed one third and two thirds of the way along the chain, revives in one twenty-fourth of the revival time, giving a faster channel and a way to deliver entangled packet states.
  • Because the hopping Hamiltonian does not touch the spin degree of freedom, the same mechanism doubles as a flying qubit and as a passive quantum fanout, sending the same spin state to several spatial receivers at once.
  • For realistic quantum-dot parameters (hopping about 10 meV and a 500-site wire), the revival time is orders of magnitude shorter than typical decoherence times, so many revivals fit within the coherence window.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The same finite Fourier machinery is not special to Gaussian packets: any low-energy state expanded in sine standing waves should show the same clone structure, so testing a rectangular or chirped initial packet would show whether shape reproduction is generic.
  • The open-chain boundary conditions force the clones to form at mirror-symmetric positions; a ring geometry would change the standing-wave basis and likely produce translation clones, a design choice the paper does not explore.
  • Each clone carries probability 1/q, so the device acts as a passive beam splitter; detecting nothing at one clone position could herald the information at another, an entanglement-distillation-style use not considered in the paper.
  • The width threshold around 24 lattice sites is an experimentally accessible crossover: sweeping the initial packet width in a dot array should show fractional fidelity collapsing below that scale, which would map the validity region of the quadratic approximation.
Original abstract

We investigate the time evolution of Gaussian wave packet (GWP) in the tight-binding chain with uniform nearest neighbor (NN) hopping integral. Analytical analysis and numerical simulations show that the fractional revival of the quantum state occurs in such system, i.e., at appropriate time, a GWP can evolve into many copies of the initial state at different positions. The application of this quantum phenomenon to the scheme of quantum information transfer in solid-state system is discussed.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-09-23: 1 request, 2,931 input tokens.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.06 · human participants 0.01 · controlled comparison 0.02 · randomized assignment 0.01 · states quantitative result 0.06 · compares with prior results 0.04 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; .

We investigate the time evolution of Gaussian wave packet (GWP) in the tight-binding chain with uniform nearest neighbor (NN) hopping integral. Analytical analysis and numerical simulations show that the fractional revival of the quantum state occurs in such system, i.e., at appropriate time, a GWP can evolve into many copies of the initial state at different positions. The application of this quantum phenomenon to the scheme of quantum information transfer in solid-state system is discussed.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 We investigate the time evolution of Gaussian wave packet (GWP) in the tight-binding chain with uniform nearest neighbor (NN) hopping integral. contribution 0.95 0.87 0.04 asserted 0.66
s1 Analytical analysis and numerical simulations show that the fractional revival of the quantum state occurs in such system, i.e., at appropriate time, a GWP can evolve into many copies of the initial state at different positions. result 1.00 0.93 0.87 asserted 1.00
s2 The application of this quantum phenomenon to the scheme of quantum information transfer in solid-state system is discussed. interpretation 0.85 0.49 0.09 unclear 0.59

What kind of paper the classifier reports this is: theoretical result 0.98 · evidence from proof or derivation 0.53.

What was examined, and what was not

sources read
  • arXiv listing abstract v2
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

Figures
Figure 1. FIG. 1: (Color online) Schematic illustrations of quantum
Figure 3. FIG. 3: The illustrations of the fractional revival via the t
Figure 5. FIG. 5: (a) Plot of the square of fidelity
Figure 6. FIG. 6: (Color online) Plot of the square of the fractional
Figure 7. FIG. 7: (Color online) The square of fractional fidelity

Showing 5 of the paper's 7 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:quant-ph/0603033 by the authors.

References
How the literature uses it

2 arXiv papers cite this in 2 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Discussion

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