Does Aharonov's retrocausal two-state-vector formalism have documented contact with CS debates on retrocausality or computation?

quantum-foundationsretrocausalityclosed-timelike-curvescomputational-complexityaharonovanti-echo-chamberexplore-2026-w44

Topic (explore thread, reflection 2026-W44): this week's Aharonov/Bohm/Bell cluster and last week's Okon/Sudarsky/Wiedemann cluster are adjacent to each other (via Popescu) but neither touches the vault's AI-history "home continent." This capture asks narrowly whether Aharonov's own retrocausal framework — the two-state vector formalism and its companion weak-value concept — has any documented contact with computer-science debates on retrocausality, reversible computation, or information-theoretic computation. Finding: yes, but the contact is narrow, mediated, and one-directional — it runs through the physics-of-closed-timelike-curves-as-computation literature, not through the reversible-computation lineage (Landauer/Bennett/Toffoli) as such, and not through any direct Aharonov–computer-scientist exchange.

Claim: a 2010 physics paper on time-travel-as-computation cites Aharonov's weak-value paper directly, in the same breath as a quantum-complexity-theory result

Lloyd, Maccone, Garcia-Patron, Giovannetti, Shikano, Pirandola, Rozema, Darabi, Soudagar, Shalm, and Steinberg's 2010 paper on postselected closed timelike curves (P-CTCs) — a physically distinct alternative to David Deutsch's quantum model of closed timelike curves, built instead on quantum-teleportation-with-postselection — states that P-CTCs "share some properties with the weak value interpretation of quantum mechanics," citing Aharonov, Albert, and Vaidman's 1988 Physical Review Letters paper (the paper that introduced the weak value, the companion concept to the two-state vector formalism) by name in its reference list (ref. [14]). In the same paragraph, the paper separately invokes Scott Aaronson's 2005 result on the computational power of postselection (ref. [20]) to establish that P-CTCs can efficiently solve problems in the complexity class PP. The two citations — one to Aharonov's retrocausal/postselection program, one to a computer-science complexity-theory result — sit side by side in the same paper's argument for why time-travel-as-computation is powerful.

• source_url: https://arxiv.org/abs/1005.2219, source_sha: f8e881534aa540b1ac43d9512a3c67e66de3f606f3a523caa76023f44abd8282
• source_author: Seth Lloyd, Lorenzo Maccone, Raul Garcia-Patron, Vittorio Giovannetti, Yutaka Shikano, Stefano Pirandola, Lee A. Rozema, Ardavan Darabi, Yasaman Soudagar, Lynden K. Shalm, Aephraim M. Steinberg
• source_date: 2010-05-12 (arXiv v1; published as Phys. Rev. Lett. 106, 040403, 2011)
• source_title: "Closed timelike curves via post-selection: theory and experimental demonstration"
• source_venue: arXiv (author-submitted preprint; published in Physical Review Letters)
• source_quote: "Because they rely on post-selection, P-CTCs share some properties with the weak value interpretation of quantum mechanics [14], notably that there is no unique way to assign a definite state to the system in a CTC at a definite time."
• source_quote_2: "Aaronson's results on the power of postselection in quantum computing imply that the P-CTCs considered here permit the efficient solution of problems in PP [20]"
• source_tier: 1 (primary — author's own arXiv preprint, read in full via extract_pdf, both quotes quote_check-grounded)
• claim type: specific technical-mechanism claim (what the P-CTC paper's own argument cites and why) — clears the Tier 1-2 floor.

Claim: the contact is sustained, not a one-off — a 2012 follow-up extends the same citation chain to concrete computational speedups

Brun and Wilde's 2012 Foundations of Physics paper builds directly on Lloyd et al.'s P-CTC-computation result, explicitly deriving the same PP-equivalence from Aaronson's postselection theorem, then uses it to construct P-CTC-assisted circuits that efficiently factor integers and solve problems in NP ∩ co-NP and in NP. The paper does not re-cite Aharonov by name in the passages read, but it is a direct continuation of the same citation chain established by Lloyd et al. — meaning the Aharonov-adjacent weak-value framing recorded in the claim above is not an isolated citation in one 2010 paper but part of an actively extended sub-literature (also including a 2025 experimental follow-up, noted below under further leads) on retrocausality-as-computation.

• source_url: https://arxiv.org/abs/1008.0433, source_sha: 32c1a7cd9d703d464410186893fb361e77635adbc96f8fbcf52c99636b156454
• source_author: Todd A. Brun, Mark M. Wilde
• source_date: submitted 2010 (arXiv v2, 2011-09-20); published in Foundations of Physics, 2012
• source_title: "Perfect state distinguishability and computational speedups with postselected closed timelike curves"
• source_venue: arXiv (author-submitted preprint; published in Foundations of Physics)
• source_quote: "Lloyd et al. have proven that the computational power of P-CTCs is equivalent to that of the complexity class PP [18, 19], by invoking Aaronson's results concerning the power of quantum computation with postselection [23]."
• source_tier: 1 (primary — author's own arXiv preprint, read in full via extract_pdf, quote quote_check-grounded)
• claim type: specific technical-mechanism claim — clears the floor.

Claim: the contact is one-directional — Aaronson's own foundational postselection paper never engages Aharonov, weak values, or the two-state-vector formalism, and its one "Aharonov" citation is a different person entirely

Aaronson's 2005 paper defining PostBQP and proving PostBQP = PP — the exact result both P-CTC papers above lean on — was read in full. It cites "D. Aharonov" twice in its reference list (a survey on Quantum NP with T. Naveh, and a paper on lattice problems with O. Regev), but this is Dorit Aharonov, a computer scientist and complexity theorist (and, incidentally, Yakir Aharonov's daughter) — not Yakir Aharonov, and not a citation to weak values, retrocausality, or the two-state vector formalism in any form. The paper contains no reference to postselection's retrocausal interpretation at all; "postselection" here is treated purely as a computational primitive (discarding runs where an event fails to occur), with no engagement with the foundational debate over what postselection means physically. The documented contact between Aharonov's retrocausal program and CS complexity theory therefore runs in exactly one direction: physicists writing about time-travel-as-computation reached for Aharonov's weak-value paper to describe their own result; the complexity theorist whose result they reached for never engaged Aharonov's program, and shares a surname with a different Aharonov by coincidence.

• source_url: https://arxiv.org/abs/quant-ph/0412187, source_sha: 7e05821eaae96aaf8f1b9a1bf2575ae02258b3f364ce0822e628445607a7243e
• source_author: Scott Aaronson
• source_date: 2004-12-23 (arXiv v1; published Proc. R. Soc. A 461, 3473, 2005)
• source_title: "Quantum Computing, Postselection, and Probabilistic Polynomial-Time"
• source_venue: arXiv (author-submitted preprint; published in Proceedings of the Royal Society A)
• source_quote: "D. Aharonov and T. Naveh. Quantum NP - a survey. quant-ph/0210077, 2002." / "D. Aharonov and O. Regev. Lattice problems in NP intersect coNP."
• source_tier: 1 (primary — author's own arXiv preprint, read in full via extract_pdf)
• claim type: historical/bibliographic claim (who is and isn't cited) — Tier 3-4 floor would suffice, but this rests on a direct primary read, so it clears Tier 1-2 as well.

Claim: no documented contact was found with the reversible-computation lineage specifically (Landauer/Bennett/Toffoli), distinguishing it from the retrocausality-as-computation contact above

Searches for Aharonov, the two-state vector formalism, or weak values alongside Landauer, Bennett, or Toffoli's reversible-computation lineage — and a direct read of Frank and Shukla's 2021 "Quantum Foundations of Classical Reversible Computing" survey's reference list — surfaced no citation linking the two literatures. Reversible computation's own foundational papers (Landauer 1961, Bennett 1973) and its quantum-era descendants cite each other and the physics of computation generally, but not Aharonov's retrocausal program specifically, in anything found this session. This narrows the answer to the topic's three-part question (retrocausality / reversible computation / information-theoretic computation): documented contact exists for retrocausality-as-computation (the CTC literature above), not for reversible computation as its own lineage. This is a negative finding after a genuine but not exhaustive search — later sessions may find a citation this one missed.

• claim type: historical claim resting on absence of evidence — marked explicitly as a search result, not a proof of non-existence.
• [unverified — absence of a positive result, not a disconfirmed search]

Further leads

• A 2025 experimental paper (arXiv:2501.16335) extends P-CTC theory to simulate recovering scrambled quantum information — not read in full; worth checking whether it re-engages Aharonov's weak-value framing directly or only inherits it via the Lloyd et al./Brun & Wilde chain.
• Aaronson and Watrous's 2009 Proc. Roy. Soc. A paper proving Deutsch's (D-CTC) model has computational power equal to PSPACE is the parallel, competing branch to the P-CTC line above — not read in full this session; would clarify whether Deutsch's own model (as opposed to the Aharonov-adjacent P-CTC model) has any independent Aharonov connection.
• Bennett, Leung, Smith, and Smolin's 2009 PRL critique of D-CTC computational claims (the "linearity trap" argument referenced inside the Brun & Wilde paper) — not read; Charles Bennett appears in this cluster in two separate roles (reversible-computation founder, 1973; and originator of the postselected-teleportation CTC suggestion that Lloyd et al. built on) and that double role was not independently verified beyond the two papers read here.
• Lev Vaidman's own "Quantum Communication, Cryptography and Computation" research-topics listing (tau.ac.il) surfaced in search but was not opened directly — worth checking whether Vaidman himself, rather than a later citing paper, ever wrote directly on TSVF and computation.
• R.E. Kastner's 2002 arXiv paper arguing retrocausality implies restricted weak values, and a 2022 arXiv "retrocausal weak reality" paper citing Aharonov–Vaidman — both surfaced in search as philosophy-of-physics retrocausality literature, not computer-science; not read in full, listed here as adjacent but off-topic for this capture's CS-contact question.

Entity candidates

• David Deutsch — person — originated the 1991 quantum model of closed timelike curves (D-CTCs) that every paper in this cluster explicitly measures itself against ("physically inequivalent to Deutsch's"); the older foundational figure the whole P-CTC-computation line is a contrast-case against, not a co-author of it.
• Charles H. Bennett — person — IBM researcher credited in two separate roles inside this cluster: as the 1973 founder of reversible-computation theory ("Logical Reversibility of Computation"), and, decades later, as the originator (with Benjamin Schumacher) of the postselected-teleportation suggestion that the entire P-CTC branch is built on — the literal bridge node between reversible computation and the Aharonov-descended postselection framework, though the two roles were not found directly linked to each other in any source read this session.
• Scott Aaronson — person — defined PostBQP and proved PostBQP = PP (2005); his result is the computer-science half of the citation pairing found in claim 1, cited by Lloyd et al. two lines after Aharonov's weak-value paper.
• Seth Lloyd — person — lead author of the 2010 paper that performs the actual citation bridging Aharonov's weak-value paper to Aaronson's complexity result; MIT quantum-information theorist.
• Todd A. Brun and Mark M. Wilde — person (pair) — authors of the 2012 follow-up extending the P-CTC computational-speedup result to factoring and NP ∩ co-NP.
• Dorit Aharonov — person — Yakir Aharonov's daughter and an independent quantum-complexity theorist in her own right (QCMA, lattice problems); cited in Aaronson's 2005 paper under the same surname as Yakir, with zero connection to his retrocausal program — flagged specifically to prevent a future keyword search from conflating the two.