REVIEW 2 major objections 6 minor 44 references
Partition Function Zeros of Paths and Normalization Zeros of ASEPS
T0 review · 2 major / 6 minor · reviewed 2026-08-10 · deepseek-v4-flash
Pith's one-line read A conformal map gives the exact thermodynamic limit of the ASEP normalization zeros as images of a circle.
desk verdict Elegant but non-novel conformal-map re-derivation of ASEP zero loci; the two-pole step is asserted not proven, but the paper deserves referee time. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The central object is $f_D(z) = (1 - \sqrt{1-4z})/2$, the generating function for a single Dyck excursion (a positive lattice path returning to the axis), which maps the disc $|z| < 1/4$ conformally onto the interior of a cardioid. The grand-canonical ASEP normalization factorizes as $Z(z,\alpha,\beta) = 1/[(1 - f_D(z)/\alpha)(1 - f_D(z)/\beta)]$, so the $N$-site normalization is the coefficient of $z^N$ in this product of two Dyck-walk generating functions. The zero locus is then read off from the earlier formula $u = 1/f(\sigma e^{is})$ for the random allocation model: the critical curve is the image of the convergence circle $|z| = \sigma$ under the conformal map, with $\sigma = 1/4$ when the square-root branch point is dominant and $\sigma = \beta(1-\beta)$ when the $\beta$-pole is dominant. This machinery converts the zero-finding problem into singularity analysis of a generating function.
What would settle it
Take $\beta = 0.6$ and $N = 2000, 4000$, compute the zeros of $Z_N(\alpha,\beta)$, and check whether any accumulate on a curve other than $\alpha = f_D(e^{is}/4)$. A complementary check is to search numerically on the integrand's Riemann sheet for solutions of $f_D(z) = \beta$ with $|z| < 1/4$ when $\beta > 1/2$; finding one would invalidate the branch-point-only locus.
Extended reading notes
Core claim
The paper's central claim is that the ASEP normalization zeros are governed by the same conformal map that solves the adsorbing Dyck walk. For $\beta \geq 1/2$ the locus is $\gamma(s) = f_D(e^{is}/4)$, the image of the circle $|z| = 1/4$; for $\beta < 1/2$ it is $\gamma(s) = f_D(\beta(1-\beta)e^{is})$, the image of the circle of radius $\beta(1-\beta)$. At the critical points the curves meet the real axis at angle $\pm 3\pi/4$ for the second-order transition at $\alpha = 1/2$, and at angle $\pi/2$ for the first-order line at $\alpha = \beta$. The line density of zeros follows from the uniformity of the source circle under the map. These loci coincide with the curves obtained by matching the real parts of the ASEP free energies in the three phases, namely $|\alpha(1-\alpha)| = 1/4$, $|\beta(1-\beta)| = 1/4$, and $|\alpha(1-\alpha)| = |\beta(1-\beta)|$.
Load-bearing premise
For $\beta \geq 1/2$, the argument assumes that the $\beta$-pole contributes no singularity inside $|z| < 1/4$ on the sheet selected by the contour integral, so the zero locus is fixed entirely by the square-root branch point; if a hidden $\beta$-dependent singularity were present there, the predicted curve would be different.
Editorial extensions
If this is right
- For $\beta \geq 1/2$, the zero locus of the ASEP normalization is the same cardioid-like curve as for adsorbing Dyck walks, so the second-order transition at $\alpha = 1/2$ shows zeros meeting the real axis at $\pm 3\pi/4$.
- For $\beta < 1/2$, the zeros lie on the image of the smaller circle of radius $\beta(1-\beta)$ and meet the real axis at right angles, signalling the first-order transition at $\alpha = \beta$.
- The density of zeros vanishes linearly near the second-order critical point (zeros are sparse there) and is finite at the first-order critical point, with value $\mu_{cr} = 4/(3\pi)$ for $\beta = 1/4$.
- The conformal-map loci reproduce the electrostatic free-energy matching conditions $|\alpha(1-\alpha)| = 1/4$, $|\beta(1-\beta)| = 1/4$, and $|\alpha(1-\alpha)| = |\beta(1-\beta)|$, so the two derivations agree.
- The same formula $u = 1/f(\sigma e^{is})$ gives the zero locus for the random allocation model, showing the ASEP result is part of a single conformal-map family.
Reading between the lines
- Beyond the paper, the same conformal-map method should apply to other pair-factorized steady-state normalizations and urn models with multiple constraints, a direction the paper only flags as open; a concrete test would be a two-constraint urn model whose generating function has two dominant singularities.
- Beyond the paper, since the density formula is exact, the spacing between consecutive zeros at finite $N$ could be predicted by integrating the pushforward density; the paper compares loci but does not compute finite-size spacings.
- Beyond the paper, the factorization into two independent Dyck walks suggests studying the joint zeros of $Z_N(\alpha,\beta)$ in both parameters at once, where the product structure may produce interacting rather than superimposed curves.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper studies the thermodynamic limit of the locus of zeros of the ASEP normalization Z_N(alpha,beta), viewed as a polynomial in alpha for fixed beta. It reviews analytic-combinatorics methods for random allocation models and for adsorbing Dyck walks, and uses the conformal-map formula (32) from the authors' earlier work [23] to write the Dyck-walk zero locus as alpha = f_D(e^{is}/4). It then extends this to the ASEP by observing that the grand-canonical normalization (58) is a product of two Dyck generating functions with fugacities 1/alpha and 1/beta. The central results are the zero loci alpha = f_D(e^{is}/4) for beta >= 1/2 and alpha = f_D(beta(1-beta)e^{is}) for beta < 1/2, together with the zero density obtained from Eq. (35). The paper also argues that these loci agree with the electrostatic matching of the real parts of the known ASEP free energies (61)-(64).
Significance. If correct, the paper gives a concise conformal-map derivation of the ASEP normalization zero locus and its density, unifying the ASEP case with the random-allocation and Dyck-walk cases. The results are consistent with earlier numerical and electrostatic calculations, and the manuscript includes direct numerical root checks at N=1000 for beta=3/4 and beta=1/4, which is a useful cross-check. The novelty is moderate: the ASEP zero locus itself was already known from [29,30,42], but the conformal-map route and the explicit density formula are presented here in a unified and accessible way. The main value of the paper is pedagogical and unifying rather than the discovery of an entirely new locus.
major comments (2)
- [Section VI, Eq. (59)] The central claim that the ASEP zero locus is given by the single-pole formula (32) is not derived for the two-pole integrand (59). The statement that the factor (1 - f_D(z)/beta)^{-1} "does not affect the limiting distribution of zeros" for beta >= 1/2 is justified neither by a Riemann-sheet argument nor by a saddle-point estimate. A partial-fraction decomposition of the integrand, 1/[(1-f_D/alpha)(1-f_D/beta)] = alpha beta/(beta-alpha)[(1/alpha)/(1-f_D/alpha) - (1/beta)/(1-f_D/beta)], shows that Z_N(alpha,beta) is a linear combination of the single-pole Dyck partition functions; the limiting zeros then follow from balancing the exponential rates of the two terms, i.e., from Re psi_D(alpha) = Re psi_D(beta). The authors should supply this balance analysis, or an explicit proof that for beta > 1/2 the beta-pole lies on a non-principal sheet and is therefore absent from the contour in (59), and that for beta < 1/2 the beta-pole term dominates. The numerical check at N=1000 for two values of beta is suggestive but is not a substitute for this step, which is load-bearing for the main result.
- [Section VI, after Eq. (59)] The boundary case beta = 1/2 is included in the formula alpha = f_D(e^{is}/4) for beta >= 1/2, but at beta = 1/2 the pole of (1 - f_D(z)/beta)^{-1} coincides with the branch point at z = 1/4. The argument that the beta-pole does not affect the locus for beta > 1/2 does not extend automatically to this degenerate point. Please either exclude beta = 1/2 or treat it separately, for example by a limiting argument or by an explicit analysis of the double singularity, and state the result at the triple point.
minor comments (6)
- [Section II, Eq. (10)] Equation (10) has a typographical error: the exponent should read ln f(z) - (n+1) ln z, not ln f(z) - (n+1) z.
- [Section VII, Eq. (60)] The definition of the free energy is missing the logarithm; it should read F = lim_{N -> infinity} (1/N) ln Z_N(alpha,beta), consistently with the logarithmic expressions in Eqs. (61)-(64).
- [Section V, Eq. (54)] The phrase "probabilistic weights (39)" after Eq. (54) is confusing: Eq. (39) defines the combinatorial weights w_D(s), while the probabilistic weights are defined in Eq. (54). Please correct the cross-reference.
- [Section VI, Figures 5 and 6] Please clarify in the captions that the variable alpha in the ASEP plays the role of the variable v in the Dyck-walk calculation, so that the locus in Figure 5 is the same curve as in Figure 2.
- [Section IV, Eq. (32)] Since formula (32) is imported from [23] and is the key tool of the paper, please state explicitly the regularity conditions under which it applies (for example injectivity of f on |z| < sigma and the precise meaning of the inverse f^{-1}) so that the two-pole extension in Section VI can be checked against these hypotheses.
- [Section IV and Eq. (57)] The summation index p in Eq. (57) conflicts with the pressure variable p introduced in Section IV; please rename one of them for clarity.
Circularity Check
No significant circularity: the ASEP zero locus is independently checked against numerical roots and electrostatic free-energy matching; the main caveat (unproved two-pole dominance) is a correctness gap, not a circular step.
full rationale
The central derivation applies the conformal-map formula (32), taken from the authors' earlier work [23], to the ASEP generating function. This is a self-citation, but the paper also re-derives the same formula within the electrostatic framework in Section VII, and the ASEP-specific application is not obtained by fitting parameters or by definition. The predicted zero loci for β ≥ 1/2 and β < 1/2 are benchmarked against numerically computed roots of the exact polynomial Z_N(α, β) from (57) at N = 1000 for β = 3/4 and β = 1/4, and they agree with the independent electrostatic free-energy matching conditions (62)-(64). No fitted parameter is renamed as a prediction, and no uniqueness theorem is imported from the authors' prior work. The main genuine weakness is that the paper asserts, rather than proves, that the fixed-β pole factor in (59) does not alter the limiting zero distribution for β ≥ 1/2: 'The term 1/(1 − β−1fD(z)) does not affect the limiting distribution of zeros in this case.' This is a statement about asymptotic dominance that could in principle be settled by a partial-fraction or saddle-point analysis; it is a correctness risk rather than a circular step, because the claimed locus is not an input to that assertion. The self-citations to [23], [30], and [42] point to parameter-free results with stated assumptions that do not include the target ASEP locus, and the numerical and electrostatic cross-checks provide independent support. Overall, the derivation is self-contained against external benchmarks, so the circularity score is low, reflecting only the presence of load-adjacent self-citations and a stated-but-unproved dominance claim.
Assumptions & free parameters
assumptions (4)
- domain assumption Formula (32): the locus of zeros is the image of the boundary circle |z|=sigma under u=1/f(z) when f is injective.
- domain assumption The ASEP normalization equals the product of two Dyck walk generating functions (Eq. (58)).
- domain assumption The ASEP normalization free energy can be treated as an equilibrium free energy for the purpose of matching real parts on phase boundaries.
- standard math Saddle point evaluation of contour integrals (31) and (59) is valid in the thermodynamic limit.
Cite this review
Pith. "Pith review of Partition Function Zeros of Paths and Normalization Zeros of ASEPS." pith.science (2026). https://pith.science/paper/KMYYFEJY
@misc{pith2026250114953,
author = {Pith},
title = {Pith review of: Partition Function Zeros of Paths and Normalization Zeros of ASEPS},
year = {2026},
howpublished = {\url{https://pith.science/paper/KMYYFEJY}},
note = {Machine review of arXiv:2501.14953}
}
read the original abstract
We exploit the equivalence between the partition function of an adsorbing Dyck walk model and the Asymmetric Simple Exclusion Process (ASEP) normalization to obtain the thermodynamic limit of the locus of the ASEP normalization zeros from a conformal map. We discuss the equivalence between this approach and using an electrostatic analogy to determine the locus, both in the case of the ASEP and the random allocation model.
Figures
Figures from the paper (3 more)
Reference graph
Works this paper leans on
-
[29]
Lee–Yang Zeros and Phase Transitions in Nonequilibrium Steady States
Blythe, R.A.; Evans, M.R. Lee–Yang Zeros and Phase Transitions in Nonequilibrium Steady States. Phys. Rev. Lett. 2002, 89, 080601
work page 2002
-
[23]
Yang-Lee Zeros for Real-Space Condensation
Burda, Z.; Johnston, D.A.; Kieburg, M. Yang-Lee Zeros for Real-Space Condensation. Phys. Rev. E 2025, 111, L012101
work page 2025
-
[1]
Statistical Theory of Equations of State and Phase Transitions
Yang, C.N.; Lee, T.D. Statistical Theory of Equations of State and Phase Transitions. I. Theory of Condensation. Phys. Rev. 1952, 87, 404–409
work page 1952
-
[2]
Statistical Theory of Equations of State and Phase Transitions
Lee, T.D.; Yang, C.N. Statistical Theory of Equations of State and Phase Transitions. II. Lattice Gas and Ising Model. Phys. Rev. 1952, 87, 410–419
work page 1952
-
[3]
Statistical Mechanics of Equilibrium and Nonequilibrium Phase Transitions
Bena, I.; Droz, M.; Lipowski, A. Statistical Mechanics of Equilibrium and Nonequilibrium Phase Transitions. Int. J. Mod. Phys. B 2005, 19, 4269–4329
work page 2005
-
[4]
The Lee–Yang theory of equi- librium and nonequilibrium phase transitions
Blythe, R.A.; Evans, M.R. The Lee–Yang theory of equi- librium and nonequilibrium phase transitions. Braz. J. Phys. 2003, 33, 464–475
work page 2003
-
[5]
On the Zeros of the Partition Function for the Ising Model
Abe, R. On the Zeros of the Partition Function for the Ising Model. Prog. Theor. Phys. 1967, 37, 1070–1072
work page 1967
-
[6]
A Theory on the Critical Behaviour of Ferro- magnets
Suzuki, M. A Theory on the Critical Behaviour of Ferro- magnets. Prog. Theor. Phys. 1967, 38, 289–291
work page 1967
Show all 44 references
-
[7]
Lectures in Theoretical Physics ; Brittin, W.E., Ed.; Gordon and Breach: New York, NY, USA, 1968; Volume VII, pp
Fisher, M.E. Lectures in Theoretical Physics ; Brittin, W.E., Ed.; Gordon and Breach: New York, NY, USA, 1968; Volume VII, pp. 1–46
1968
-
[8]
Properties of Higher-Order Phase Transitions
Janke, W.; Johnston, D.A.; Kenna, R. Properties of Higher-Order Phase Transitions. Nucl. Phys. B 2006, 736, 319–338
2006
-
[9]
Partition Function Zeros at First-Order Phase Transitions: A General Analysis, Commun
Biskup, M.; Borgs, C; Chayes, J.T.; Kleinwaks, L.J.; Koteck´ y, R. Partition Function Zeros at First-Order Phase Transitions: A General Analysis, Commun. Math. Phys. 2004, 251, 79–131
2004
-
[10]
General Theory of Lee–Yang Zeros in Mod- els with First-Order Phase Transitions, Phys
Biskup, M.; Borgs, C; Chayes, J.T.; Kleinwaks, L.J.; Koteck´ y, R. General Theory of Lee–Yang Zeros in Mod- els with First-Order Phase Transitions, Phys. Rev. Lett. 2000, 84, 4794–4797
2000
-
[11]
Unusual Analytic Properties of Some Lattice Models: Complement of Lee–Yang Theory, Teor
Shlosman, S.B. Unusual Analytic Properties of Some Lattice Models: Complement of Lee–Yang Theory, Teor. Mat. Fiz. 1986, 69, 273–278
1986
-
[12]
Complex-Temperature Singu- larities of the Susceptibility in the d = 2 Ising Model
Matveev, V.; Shrock, R. Complex-Temperature Singu- larities of the Susceptibility in the d = 2 Ising Model. I. Square Lattice. J. Phys. A 1995, 28, 1557–1573
1995
-
[13]
Distribution of zeros of the partition function for the one dimensional Ising models
Katsura, S.; Ohminami, M. Distribution of zeros of the partition function for the one dimensional Ising models. 10 J. Phys. A 1972, 5, 95–105
1972
-
[14]
The partition function zeros in the one-dimensional q-state Potts model
Glumac, Z.; Uzelac, K. The partition function zeros in the one-dimensional q-state Potts model. J. Phys. A 1994, 27, 7709–7720
1994
-
[15]
Partition function zeros of the one-dimensional Potts model: The recursive method
Ghulghazaryan, R.G.; Ananikian, N.S. Partition function zeros of the one-dimensional Potts model: The recursive method. J. Phys. A 2003, 36, 6297–6305
2003
-
[16]
Partition function zeros for the Ising model on complete graphs and on annealed scale-free networks
Krasnytska, M.; Berche, B.; Holovatch, Y.; Kenna, R. Partition function zeros for the Ising model on complete graphs and on annealed scale-free networks. J. Phys. A 2016, 49, 135001
2016
-
[17]
Distribution of Zeros in Ising and Gauge Models
Itzykson, C.; Pearson, R.; Zuber, J.B. Distribution of Zeros in Ising and Gauge Models. Nucl. Phys. B 1983, 220, 415–433
1983
-
[18]
Partition Function Zeros for Aperiodic Systems
Baake, M.; Grimm, U.; Pisani, C. Partition Function Zeros for Aperiodic Systems. J. Stat. Phys. 1995, 78, 285–297
1995
-
[19]
Planar quasiperiodic Ising models Mater
Repetowicz, P.; Grimm, U.; Schreiber, M. Planar quasiperiodic Ising models Mater. Sci. Eng. A 2000, 294–296, 638–641
2000
-
[20]
The zeroes of the partition function of the random energy model
Derrida, B. The zeroes of the partition function of the random energy model. Physica A 1991, 177, 31–37
1991
-
[21]
The Yang-Lee edge singularity on a dy- namical planar random surface.Nucl
Staudacher, M. The Yang-Lee edge singularity on a dy- namical planar random surface.Nucl. Phys. B 1990, 336, 349–362
1990
-
[22]
Fat Fisher Zeroes
Janke, W.; Johnston, D.A.; Stathakopoulos, M. Fat Fisher Zeroes. Nucl. Phys. B 2001, 614, 494–514
2001
-
[24]
Analytic Combinatorics ; Cambridge University Press: Cambridge, UK, 2009
Flajolet, P.; Sedgewick, R. Analytic Combinatorics ; Cambridge University Press: Cambridge, UK, 2009
2009
-
[25]
Condensation for random variables condi- tioned by the value of their sum J
Godr` eche, C. Condensation for random variables condi- tioned by the value of their sum J. Stat. Mech. 2019, 063207
2019
-
[26]
Condensation and Extremes for a Fluctu- ating Number of Independent Random Variables.J
Godr` eche, C. Condensation and Extremes for a Fluctu- ating Number of Independent Random Variables.J. Stat. Phys. 2021, 182, 13
2021
-
[27]
Nonequilibrium dynamics of a simple stochastic model
Godr` eche, C.; Luck, J.M. Nonequilibrium dynamics of a simple stochastic model. J. Phys. A 1997, 30, 6245–6264
1997
-
[28]
Probability Distributions with Singularities
Corberi, F.; Sarracino, A. Probability Distributions with Singularities. Entropy 2019, 21, 312
2019
-
[30]
The Grand-Canonical Asymmetric Exclusion Process and the One-Transit Walk
Blythe, R.A.; Janke, W.; Johnston, D.A.; Kenna, R. The Grand-Canonical Asymmetric Exclusion Process and the One-Transit Walk. J. Stat. Mech. 2004, P06001
2004
-
[31]
Glassiness in a Model without Energy Barriers
Ritort, F. Glassiness in a Model without Energy Barriers. Phys. Rev. Lett. 1995, 75, 1190–1193
1995
-
[32]
Condensation in the Backgammon Model
Bialas, P.; Burda, Z.; Johnston, D. Condensation in the Backgammon Model. Nucl. Phys. B 1997, 493, 505–516
1997
-
[33]
¨Uber zwei bekannte Einw¨ ande gegen das Boltzmannsche H-Theorem
Ehrenfest, P.; Ehrenfest, T. ¨Uber zwei bekannte Einw¨ ande gegen das Boltzmannsche H-Theorem. Phys. Zeit. 1907, 8, 311–314
1907
-
[34]
Phase Transition in Fluctuating Branched Geometry
Bialas, P.; Burda, Z. Phase Transition in Fluctuating Branched Geometry. Phys. Lett. B 1996, 384, 75–80
1996
-
[35]
Glassy Mean-Field Dynamics of the Backgammon Model
Franz, S.; Ritort, F. Glassy Mean-Field Dynamics of the Backgammon Model. J. Stat. Phys. 1996, 85, 131–150
1996
-
[36]
Phase Diagram of the Mean Field Model of Simplicial Gravity
Bialas, P.; Burda, Z.; Johnston, D. Phase Diagram of the Mean Field Model of Simplicial Gravity. Nucl. Phys. B 1999, 542, 413–424
1999
-
[37]
Random Alloca- tion Models in the Thermodynamic Limit
Bialas, P.; Burda, Z.; Johnston, D. Random Alloca- tion Models in the Thermodynamic Limit. Phys. Rev. E 2023, 108, 064107
2023
-
[38]
R´ enyi Entropy of Zeta Urns
Bialas, P.; Burda, Z.; Johnston, D. R´ enyi Entropy of Zeta Urns. Phys. Rev. E 2023, 108, 064108
2023
-
[39]
Partition Function Zeros of Zeta-Urns
Bialas, P.; Burda, Z.; Johnston, D. Partition Function Zeros of Zeta-Urns. Condens. Matter Phys. 2024, 27, 33601
2024
-
[40]
The Statistical Mechanics of Interacting Walks, Polygons, Animals and Vesicles ; Ox- ford University Press: Oxford, UK, 2000; pp
Janse van Rensburg, E.J. The Statistical Mechanics of Interacting Walks, Polygons, Animals and Vesicles ; Ox- ford University Press: Oxford, UK, 2000; pp. 98–104
2000
-
[41]
Exact Solution of a 1D Asymmetric Exclusion Model Using a Matrix Formulation
Derrida, B.; Evans, M.R.; Hakim, V.; Pasquier, V. Exact Solution of a 1D Asymmetric Exclusion Model Using a Matrix Formulation. J. Phys. A Math. Gen. 1993, 26, 1493–1517
1993
-
[42]
Dyck Paths, Motzkin Paths and Traffic Jams
Blythe, R.A.; Janke, W.; Johnston, D.A.; Kenna, R. Dyck Paths, Motzkin Paths and Traffic Jams. J. Stat. Mech. 2004, P10007
2004
-
[43]
Combinatorial Mappings of Exclusion Processes
Wood, A.J.; Blythe, R.A.; Evans, M.R. Combinatorial Mappings of Exclusion Processes. J. Phys. A: Math. Theor. 2020, 53, 123001
2020
-
[1000]
free energy
In this case, the critical curve impacts the real axis at an angle π/2, which is characteristic of a first-order transition. The density of zeros at this first-order phase FIG. 6. Analytically calculated locus of zeros in the ther- modynamic limit from Z(z, α, β) and numerical...
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