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Trapped-Ion Page-Wootters Experiment: Protocol for Testing Ultrametricity

Rowan Brad Quni-Gudzinas

Published Jul 2, 2026• 0 citations
Publisher

Abstract

We propose a trapped-ion experiment to test the Sufficient Condition Theorem: that diagonal clock-rest coupling in the clock eigenbasis produces exact ultrametric conditional state overlaps (UVR = 0%), while nondiagonal coupling produces a universal ~32% violation rate. The experiment uses a single trapped ion with internal electronic states as the clock and motional Fock states as the rest system. Laser-driven carrier and sideband transitions provide tunable diagonal/nondiagonal coupling. Conditional state tomography at multiple clock readings yields the overlap matrix, whose Parisi ultrametricity violation rate is the observable. All required capabilities are established with current trapped-ion technology. Estimated timeline: 8 weeks on an existing apparatus. If confirmed, this experiment verifies the physical foundations of the Bridge Theorem connecting Page-Wootters conditional states to Bruhat-Tits buildings, with implications for CMB phenomenology and p-adic holography.

DOI
10.5281/zenodo.21120468

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Development and implementation of an Yb+ ion trap experiment towards coherent manipulation and entanglement

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Trapped ions are currently one of the most promising architectures for realising the quantum information processor. The long lived internal states are ideal for representing qubit states and, through controlled interactions with electromagnetic radiation, ions can be manipulated to execute coherent logic operations. In this thesis an experiment capable of trapping Yb+ ions, including 171Yb+, is presented. Since ion energy can limit the coherence of qubit manipulations, characterisation of an ion trap heating rate is vital. Using a trapped 174Yb+ ion a heating rate consistent with previous measurements of other ion species in similar ion traps is obtained. This result shows abnormal heating of Yb+ does not occur, further solidifying the suitability of this species for quantum information processing. Efficient creation, and cooling of trapped ions requires exact wavelengths for the ionising, cooling and repump transitions. A simple technique to measure the 1S0 ? 1P1 transition wavelengths, required for isotope selective photoionisation of neutral Yb, is developed. Using the technique new wavelengths, accurate to 60 MHz, are obtained and differ from previously published results by 660 MHz. Through a simple modification the technique can also predict Doppler shifted transition frequencies, which may be required in non-perpendicular atom-laser interactions. Using trapped ions, the 2S1=2 ? 2P1/2 Doppler cooling and 2D3/2 ? 2D[3/2]1/2 repump transitions are also measured to a greater accuracy than previously reported. Many experiments require wavelengths which can only be obtained using complex expensive laser systems. To remedy this a simple cost effective laser is developed to enable laser diodes to be operated at sub zero temperatures, extending the range of obtainable wavelengths. Additional diode modulation capabilities allow for the manipulation of atoms and ions with hyperfine structures. The laser is shown to be suitable for manipulating Yb+ ions by cooling a diode from 372 nm to 369 nm and simultaneously generating 2.1 GHz frequency sidebands. Coherent manipulation such as arbitrary qubit rotations, motional coupling and ground state cooling, are required for trapped ion quantum computing. Two photon stimulated Raman transitions are identified as a suitable technique to implement all of these requirements and an investigation into implementing this technique with 171Yb+ is conducted. The possibility of exciting a Raman transition via either a dipole or quadrupole transitions in 171Yb+ is analysed, with dipole transitions preferred because quadrupole transitions are found to be too demanding experimentally. An inexpensive setup, utilising a dipole transition, is designed and tested. Although currently limited the setup shows potential to be an inexpensive, high fidelity method of exciting a Raman transition.

•Apr 20, 2012•1 citation
We propose a trapped-ion experiment to test the Sufficient Condition Theorem: that diagonal clock-rest coupling in the clock eigenbasis produces exact ultrametric conditional state overlaps (UVR = 0%), while nondiagonal coupling produces a universal ~32% violation rate. The experiment uses a single trapped ion with internal electronic states as the clock and motional Fock states as the rest system. Laser-driven carrier and sideband transitions provide tunable diagonal/nondiagonal coupling. Conditional state tomography at multiple clock readings yields the overlap matrix, whose Parisi ultrametricity violation rate is the observable. All required capabilities are established with current trapped-ion technology. Estimated timeline: 8 weeks on an existing apparatus. If confirmed, this experiment verifies the physical foundations of the Bridge Theorem connecting Page-Wootters conditional states to Bruhat-Tits buildings, with implications for CMB phenomenology and p-adic holography.
Sixteen published records from a single research program, spanning December 2025 to August 2026, are here organized into one testable claim: trapped-ion quantum simulators are the first near-term platform on which ultrametric (p-adic) structure in quantum dynamics can be accepted or rejected by measurement, and passive, dissipation-structured hardware is the engineering embodiment of that structure. The synthesis contributes a falsifiability register: five observables, each with a pre-registered prediction, a kill-condition, and an apparatus already demonstrated in the cited records. It also records what the program has already ruled out, including the finding that generic Page-Wootters clock-rest coupling violates ultrametricity at a 29-35 percent rate while diagonal coupling yields exact ultrametric structure -- the very asymmetry the trapped-ion protocol measures -- and the economic finding that trapped ions rank last among seventeen platforms on a joules-per-solution basis, making the ion trap a physics testbed rather than a production economics play. The paper discloses its premise depth: the falsifiable content rests on two named imported inputs, and the claims end where those inputs begin. A practitioner section specifies what can be built today without any new theory.
A response to Pikovski et al. (Phys. Rev. Lett., 2026), who predict that a trapped ion in a motional superposition will exhibit measurable clock-transition blurring, interpreted as evidence that time itself exists in quantum superposition. We show that the identical observable arises in a framework where the tick rate is set by the local amplitude of a decaying background field (Zuhars, The Self-Interacting Universe, 2026). The ion's motional wavepacket samples different background amplitudes at different spatial positions, producing the same phase spread without requiring time to be a quantum observable. The two interpretations make a distinguishable experimental prediction: varying the trap frequency while holding the quantum state fixed produces different scaling in the two frameworks. We identify the specific signature and propose the test.
This record bundles two engagement artifacts derived from the v1.4 register of the Trapped-Ion Ultrametric Testbed (10.5281/zenodo.22025544): (1) industry-brief-2026-08-20.md — "Why Measure Error Correlations Before Choosing a Code": a one-page brief answering whether the ultrametric quantum error-correction path is worth pursuing given its published independent-error threshold disadvantage (~55x below surface codes). The brief leads with the honest disclosure, frames the single falsifiable bet (error structure at scale is not independent), and offers four theory-neutral instruments (an 8-week trapped-ion probe, a laptop benchmark, an energy-audit template, and a QEC-Darwinism constraint checker). (2) correlated-error-benchmark-spec-2026-08-20.md — a pre-registered measurement protocol with six observables, five metrics, and three binding decision rules (including KILL-ULTRAMETRIC, which is binding on the program itself). The protocol is theory-neutral: the correlation metrics improve any code choice, ultrametric or not. Both artifacts are published as open engagement documents; the register's decision rules and kill-conditions are pre-registered. No hardware-advantage claim is made in either document.
Abstract We present a protocol to produce a class of non-thermal Fock state mixtures in trapped ions. This class of states features a clear metrological advantage with respect to the ground state, thus overcoming the standard quantum limit without the need for full sideband cooling and Fock-state preparation on a narrow electronic transition. The protocol consists in the cyclic repetition of red-sideband (RSB), measurement and preparation laser pulses. By means of the Kraus map representation of the protocol, it is possible to relate the length of the RSB pulses to the specific class of states that can be generated. With the help of numerical simulations, we analyse the parametric regime where these states can be reliably reproduced.
The purpose of this work is to investigate methods by which the quantum states of trapped ions may be better controlled and measured for the applications of quantum computing, quantum simulation, and the generation of atomic frequency standards. We report on two primary projects: first, we control the relative coupling strengths of carrier and first-order motional sideband interactions of a trapped ion by placing it in a resonant optical standing wave. Our configuration uses the surface of a microfabricated chip trap as a mirror, avoiding the technical challenges of in-vacuum optical cavities. Displacing the ion along the standing wave, we show a periodic suppression of the carrier and sideband transitions, with the cycles for the two cases 180◦ out of phase with each other. This technique allows for the suppression of off-resonant carrier excitations when addressing the motional sidebands, and has applications in quantum computation and quantum simulation. Second, we investigate methods proposed in Ref. [36] which may improve the performance of trapped ion (or atom) frequency standards when the interrogating local oscillator is of limited quality. These methods could be applied to future generations of small-scale frequency standards, which are in demand for applications such as local GPS networks and distributed sensors. We propose a scheme for implementing these methods in a 40Ca+ based frequency standard, and outline the technical requirements for doing so. Finally, we present preliminary results characterizing single-ion coherence times and ion “state destruction” events in our system, and discuss how they will affect the realization of the proposed scheme.
Trapped ions are currently one of the most promising architectures for realising the quantum information processor. The long lived internal states are ideal for representing qubit states and, through controlled interactions with electromagnetic radiation, ions can be manipulated to execute coherent logic operations. In this thesis an experiment capable of trapping Yb+ ions, including 171Yb+, is presented. Since ion energy can limit the coherence of qubit manipulations, characterisation of an ion trap heating rate is vital. Using a trapped 174Yb+ ion a heating rate consistent with previous measurements of other ion species in similar ion traps is obtained. This result shows abnormal heating of Yb+ does not occur, further solidifying the suitability of this species for quantum information processing. Efficient creation, and cooling of trapped ions requires exact wavelengths for the ionising, cooling and repump transitions. A simple technique to measure the 1S0 ? 1P1 transition wavelengths, required for isotope selective photoionisation of neutral Yb, is developed. Using the technique new wavelengths, accurate to 60 MHz, are obtained and differ from previously published results by 660 MHz. Through a simple modification the technique can also predict Doppler shifted transition frequencies, which may be required in non-perpendicular atom-laser interactions. Using trapped ions, the 2S1=2 ? 2P1/2 Doppler cooling and 2D3/2 ? 2D[3/2]1/2 repump transitions are also measured to a greater accuracy than previously reported. Many experiments require wavelengths which can only be obtained using complex expensive laser systems. To remedy this a simple cost effective laser is developed to enable laser diodes to be operated at sub zero temperatures, extending the range of obtainable wavelengths. Additional diode modulation capabilities allow for the manipulation of atoms and ions with hyperfine structures. The laser is shown to be suitable for manipulating Yb+ ions by cooling a diode from 372 nm to 369 nm and simultaneously generating 2.1 GHz frequency sidebands. Coherent manipulation such as arbitrary qubit rotations, motional coupling and ground state cooling, are required for trapped ion quantum computing. Two photon stimulated Raman transitions are identified as a suitable technique to implement all of these requirements and an investigation into implementing this technique with 171Yb+ is conducted. The possibility of exciting a Raman transition via either a dipole or quadrupole transitions in 171Yb+ is analysed, with dipole transitions preferred because quadrupole transitions are found to be too demanding experimentally. An inexpensive setup, utilising a dipole transition, is designed and tested. Although currently limited the setup shows potential to be an inexpensive, high fidelity method of exciting a Raman transition.