REVIEW 2 major objections 1 minor 45 references
Minimum uncertainty states and squeezed states from the sum uncertainty relation
T0 review · 2 major / 1 minor · reviewed 2026-05-23 · grok-4.3
Pith's one-line read The minimum uncertainty states for the sum uncertainty relation are always the minimum uncertainty states for the product uncertainty relation.
desk verdict The paper recovers the usual coherent and squeezed minimizers via variational calc on the sum relation for two operator pairs, but the 'always' claim has no general derivation. 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
Variational minimization of the sum uncertainty relation, which identifies states saturating its bound and shows they also saturate the product bound.
What would settle it
Discovery of a quantum state that achieves the minimum value of the sum uncertainty relation but fails to achieve the minimum of the product uncertainty relation for position and momentum would falsify the claim.
Extended reading notes
Core claim
The minimum uncertainty states for the sum uncertainty relation are always the minimum uncertainty states for the traditional product uncertainty relation, as demonstrated by variational minimization applied to the position-momentum pair and angular momentum operators. Coherent and squeezed states of radiation remain completely unaffected by the sum uncertainty relation.
Load-bearing premise
The variational minimization performed on the sum uncertainty relation for the position-momentum and angular momentum pairs captures the global minimum and extends to other cases.
Editorial extensions
If this is right
- Coherent states minimize both the sum and product uncertainty relations.
- Squeezed states also minimize the sum uncertainty relation without adjustment.
- No new minimum uncertainty states arise from the sum relation in the examined operator pairs.
- The sum relation provides a stronger numerical bound but shares the same extremal states as the product relation.
Reading between the lines
- The equivalence may suggest that the sum relation's advantage lies in its tighter bound value rather than in redefining the states that achieve it.
- If the pattern holds for other operator pairs, the sum relation could be used interchangeably with the product relation when identifying minimum uncertainty states.
- Quantum optics applications involving coherent or squeezed light may require no revision to account for the sum relation.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript claims that the minimum-uncertainty states of the Maccone-Pati sum uncertainty relation coincide with those of the Heisenberg-Robertson product uncertainty relation. This is asserted on the basis of a variational minimization performed on the sum relation for the position-momentum pair and for angular-momentum operators, from which the authors conclude that coherent and squeezed states remain the minimizers and are unaffected by the sum relation.
Significance. If the claim holds, the result would imply that the stronger sum uncertainty relation does not generate new classes of minimum-uncertainty states beyond those already identified by the product relation. The concrete variational calculations for the two operator pairs constitute a modest positive contribution, but the absence of a general argument or additional operator families limits the significance.
major comments (2)
- [Abstract] Abstract: the universal claim that the minimum-uncertainty states 'are always' those of the product relation is load-bearing yet unsupported by any derivation showing that the stationarity condition obtained from varying ΔA² + ΔB² is mathematically equivalent to that obtained from varying ΔA ΔB for arbitrary non-commuting A and B; only two specific pairs are examined.
- [Variational approach] The variational minimization (described after the abstract): no demonstration is given that the observed coincidence with the known product minimizers (coherent/squeezed states) is the global minimum rather than a local extremum, nor is an error analysis or completeness check for the operator examples supplied.
minor comments (1)
- [Abstract] The abstract statement that the sum relation is 'claimed to be stronger' would benefit from a brief reminder of the precise sense in which Maccone-Pati is stronger than Heisenberg-Robertson.
Simulated Author's Rebuttal
We thank the referee for the careful reading and constructive comments. We respond point by point to the major comments and agree that the manuscript's phrasing requires qualification to reflect the limited scope of the calculations.
read point-by-point responses
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Referee: [Abstract] Abstract: the universal claim that the minimum-uncertainty states 'are always' those of the product relation is load-bearing yet unsupported by any derivation showing that the stationarity condition obtained from varying ΔA² + ΔB² is mathematically equivalent to that obtained from varying ΔA ΔB for arbitrary non-commuting A and B; only two specific pairs are examined.
Authors: We accept the point. The abstract and main text use the word 'always' on the basis of explicit variational calculations performed only for the position-momentum pair and for angular-momentum operators. No general proof is given that the stationarity conditions derived from δ(ΔA² + ΔB²) = 0 are equivalent to those from δ(ΔA ΔB) = 0 for arbitrary non-commuting operators. We will revise the abstract, introduction, and conclusion to remove the universal claim and to state clearly that the coincidence of minimizers is demonstrated for the two operator families examined. revision: yes
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Referee: [Variational approach] The variational minimization (described after the abstract): no demonstration is given that the observed coincidence with the known product minimizers (coherent/squeezed states) is the global minimum rather than a local extremum, nor is an error analysis or completeness check for the operator examples supplied.
Authors: The variational procedure sets the first variation of the sum uncertainty to zero and obtains differential equations whose solutions coincide with the known coherent and squeezed states. This shows that those states are stationary points for the sum relation, but the calculation does not include a second-variation test, a search over a larger function space, or error estimates to establish that the stationary point is the global minimum. We will insert a short paragraph acknowledging these limitations of the variational method and noting that the identification rests on matching to the independently established global minimizers of the product relation. revision: partial
Circularity Check
No circularity; claim rests on explicit variational calculations for specific cases
full rationale
The paper performs a variational minimization directly on the Maccone-Pati sum uncertainty relation for the position-momentum pair and for angular-momentum operators, then observes that the resulting states coincide with the known coherent and squeezed states that minimize the Heisenberg-Robertson product relation. No equation is defined in terms of its own output, no fitted parameter is relabeled as a prediction, and no load-bearing premise is justified solely by self-citation. The derivation chain is therefore self-contained against the explicit stationarity conditions obtained in the two examples; the universal phrasing 'always' is an extrapolation rather than a definitional reduction.
Assumptions & free parameters
assumptions (2)
- standard math Quantum states are represented by vectors in Hilbert space and observables by self-adjoint operators whose commutators define uncertainty bounds.
- domain assumption The variational method applied to the sum uncertainty functional yields its global minimum for the chosen operator pairs.
Cite this review
Pith. "Pith review of Minimum uncertainty states and squeezed states from the sum uncertainty relation." pith.science (2026). https://pith.science/paper/6LIRJDH6
@misc{pith2026240716530,
author = {Pith},
title = {Pith review of: Minimum uncertainty states and squeezed states from the sum uncertainty relation},
year = {2026},
howpublished = {\url{https://pith.science/paper/6LIRJDH6}},
note = {Machine review of arXiv:2407.16530}
}
read the original abstract
Heisenberg uncertainty relation is at the origin of understanding minimum uncertainty states and squeezed states of light. In the recent past, sum uncertainty relation was formulated by Maccone and Pati [Maccone and Pati, Phys. Rev. Lett. 113, 260401 (2014)] which is claimed to be stronger than the existing Heisenberg-Robertson product uncertainty relation. We analyze the minimum uncertainty states for the sum uncertainty relation using the variational approach. We claim that the minimum uncertainty states for the sum uncertainty relation are always the minimum uncertainty states for the traditional product uncertainty relation, using the example of position-momentum pair as well as angular momentum operators. We show that the coherent and squeezed states of radiation remain completely unaffected by the sum uncertainty relation.
Figures
Lean theorems connected to this paper
-
IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
We claim that the minimum uncertainty states for the sum uncertainty relation are always the minimum uncertainty states for the traditional product uncertainty relation, using the example of position-momentum pair as well as angular momentum operators.
-
IndisputableMonolith/Foundation/AbsoluteFloorClosure.leanabsolute_floor_iff_bare_distinguishability unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
ΔA² + ΔB² ≥ ±i⟨[A,B]⟩ (weaker sum relation derived via AM-GM)
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
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Minimum uncertainty states and squeezed states from the sum uncertainty relation
A squeezed state [25] is defined as the state for which the variance is smaller than that of the corresponding co- herent state, i.e., ∆ X 2 1 < 1 4 represents squeezed state in X1 quadrature. The generalization of the concept of squeezed state is also established in the context of polar- ization squeezing [41, 42] and spin squeezing [28] in the field of ...
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This is no different than the the existing definition of squeezed states. (a) (b) FIG. 1: θ dependence for the observables Jz and Jy for the state |ψ⟩ = 1√ 2 [cos θ |1⟩ + sin θ |−1⟩ + |0⟩], where |1⟩, |−1⟩ and |0⟩ are the eigenstates of Jz operator. The red curve is the first term of the RHS of inequality (5), the green is the LHS of inequality (5), the b...
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