We perform quantum non-demolition (QND) photon counting on a microwave field trapped in a very high Q superconducting cavity, employing circular Rydberg atoms as non-absorbing light probes. Beyond realizing fundamental tests of quantum measurement theory, we use this QND method to prepare non-classical Fock and Schrodinger cat states of the field and to reconstruct their Wigner functions. Monitoring the evolution of these functions provides a direct observation of the decoherence process. Quantum feedback procedures will enable us to steer the field towards target states and to protect them against decoherence.We perform quantum non-demolition (QND) photon counting on a microwave field trapped in a very high Q superconducting cavity, employing circular Rydberg atoms as non-absorbing light probes. Beyond realizing fundamental tests of quantum measurement theory, we use this QND method to prepare non-classical Fock and Schrodinger cat states of the field and to reconstruct their Wigner functions. Monitoring the evolution of these functions provides a direct observation of the decoherence process. Quantum feedback procedures will enable us to steer the field towards target states and to protect them against decoherence.

Physica ScriptaDec 1, 20091 citation

Single-photon quantum non-demolition measurements

Pieter Kok, H. Lee, Jonathan P. Dowling

Oct 1, 20020 citations

PROGRESSIVE FIELD-STATE COLLAPSE, RELATIONAL OBSERVATION, AND INFORMATION

Vidamor Cabannas

This article develops an expanded critical–propositional analysis of Christine Guerlin et al.’s 2007 experimental study, “Progressive Field-State Collapse and Quantum Non- Demolition Photon Counting,” published in Nature, in systematic dialogue with the Theory of Objectivity (TO) formulated by Vidamor Cabannas and Denivaldo Silva. Guerlin et al. experimentally followed the progressive measurement-induced reduction of a coherent microwave field toward photon-number, or Fock, states by means of repeated quantum non-demolition (QND) interrogations using circular Rydberg atoms. Rather than absorbing the photons under investigation, successive atoms acquired photon-number-dependent phase shifts through dispersive atom–field coupling. The accumulated sequence of atomic detections progressively reduced uncertainty regarding the field’s photon number until a discrete value emerged, while further QND measure- ments repeatedly recovered the same result until cavity damping produced a quantum jump (Guerlin et al. 2007). The experiment is especially relevant to TO because interaction, correlation, boundary conditions, physical fields, non-anthropocentric observation, information acquisition, progressive determination, and repeatability occur within a single carefully controlled physical architecture. The present analysis nevertheless maintains a strict epistemological distinction between empirical compatibility and the modal necessity claimed for the axioms of TO. A finite experiment cannot establish the logical necessity of an axiom merely by exemplifying a physical structure compatible with it. Accordingly, the central question is not whether Guerlin et al. “prove” TO, but whether their empirical results are compatible with specific TO propositions, whether they create points of tension, and whether they suggest operational bridges capable of generating independently testable predictions. Particular attention is devoted to the First Absolute Truth, according to which prior to the physical universe there was Nothing, where this Nothing is not absolute non-being but an eternal logical and mathematical essence; the Second Absolute Truth, according to which every existing element possesses its own exclusive magnetic field as a principle of physical individuation; and the Fifth Absolute Truth, according to which an element requires relational observation or inclusion within the frequency of at least two other elements for logical existence, with observation explicitly understood as non-human. The strongest domains of dialogue concern the Fourth, Fifth, Sixth, and Seventh Absolute Truths. The superconducting cavity illustrates the constitutive role of physical boundaries. The atom–field–detector chain provides a non-anthropocentric architecture of physical observation. The progressive Bayesian narrowing of the photon-number distribution provides an unusually clear example of cumulative determination through successive previous relations. Finally, information about the electromagnetic field becomes physically encoded in the state of successive atoms through microscopic interactions. This last point creates both the strongest compatibility and the most important tension with TO. In the formulation considered here, TO identifies the transcendent element with knowledge or information generated in atomic relations and regards that information as equivalent to atomic radiation. Guerlin et al. strongly support the first part of this claim at the operational level: physical information is produced or instantiated through atom–field relations. However, QND measurement is deliberately dispersive and suppresses ordinary real photon absorption and emission. Information can therefore be gained while conventional radiative exchange is extremely small. The experiment consequently does not establish a strict identity between information and emitted atomic radiation. To transform this conceptual tension into empirical progress, the article pro- poses an experimental program in which Shannon information gain, atom–field mutual information, atomic phase shifts, field-energy changes, emitted radiative energy, and environmental exchange are separately quantified. A TO-specific physical prediction would require a measurable quantity or residual not already predicted by standard quantum electrodynamics. The analysis further examines possible relations to TO’s phenomenic elements, Inductor Effects, cosmogonic theorem, and cosmological Eras while avoiding unsupported cosmological extrapolation from a laboratory experiment. In dialogue with Heisenberg, Einstein, Bohm, Prigogine, Kuhn, Penrose, Zurek, Aspect, Planck, LIGO/Virgo, JWST observations, and the foundational and recent literature of TO, the study concludes that Guerlin et al. constitute a particularly valuable empirical interlocutor for the relational and informational dimensions of TO but do not provide exclusive confirmation of the theory. The final assessment places the article at 8.5/10 on a scale measuring the substantive degree of dialogue with the Theory of Objectivity. Keywords: Theory of Objectivity; quantum non-demolition measurement; photon counting; cavity quantum electrodynamics; Rydberg atoms; quantum information; relational observation; field-state collapse; Fock states; modal ontology; information; atomic radiation; Inductor Effects.This article develops an expanded critical–propositional analysis of Christine Guerlin et al.’s 2007 experimental study, “Progressive Field-State Collapse and Quantum Non- Demolition Photon Counting,” published in Nature, in systematic dialogue with the Theory of Objectivity (TO) formulated by Vidamor Cabannas and Denivaldo Silva. Guerlin et al. experimentally followed the progressive measurement-induced reduction of a coherent microwave field toward photon-number, or Fock, states by means of repeated quantum non-demolition (QND) interrogations using circular Rydberg atoms. Rather than absorbing the photons under investigation, successive atoms acquired photon-number-dependent phase shifts through dispersive atom–field coupling. The accumulated sequence of atomic detections progressively reduced uncertainty regarding the field’s photon number until a discrete value emerged, while further QND measure- ments repeatedly recovered the same result until cavity damping produced a quantum jump (Guerlin et al. 2007). The experiment is especially relevant to TO because interaction, correlation, boundary conditions, physical fields, non-anthropocentric observation, information acquisition, progressive determination, and repeatability occur within a single carefully controlled physical architecture. The present analysis nevertheless maintains a strict epistemological distinction between empirical compatibility and the modal necessity claimed for the axioms of TO. A finite experiment cannot establish the logical necessity of an axiom merely by exemplifying a physical structure compatible with it. Accordingly, the central question is not whether Guerlin et al. “prove” TO, but whether their empirical results are compatible with specific TO propositions, whether they create points of tension, and whether they suggest operational bridges capable of generating independently testable predictions. Particular attention is devoted to the First Absolute Truth, according to which prior to the physical universe there was Nothing, where this Nothing is not absolute non-being but an eternal logical and mathematical essence; the Second Absolute Truth, according to which every existing element possesses its own exclusive magnetic field as a principle of physical individuation; and the Fifth Absolute Truth, according to which an element requires relational observation or inclusion within the frequency of at least two other elements for logical existence, with observation explicitly understood as non-human. The strongest domains of dialogue concern the Fourth, Fifth, Sixth, and Seventh Absolute Truths. The superconducting cavity illustrates the constitutive role of physical boundaries. The atom–field–detector chain provides a non-anthropocentric architecture of physical observation. The progressive Bayesian narrowing of the photon-number distribution provides an unusually clear example of cumulative determination through successive previous relations. Finally, information about the electromagnetic field becomes physically encoded in the state of successive atoms through microscopic interactions. This last point creates both the strongest compatibility and the most important tension with TO. In the formulation considered here, TO identifies the transcendent element with knowledge or information generated in atomic relations and regards that information as equivalent to atomic radiation. Guerlin et al. strongly support the first part of this claim at the operational level: physical information is produced or instantiated through atom–field relations. However, QND measurement is deliberately dispersive and suppresses ordinary real photon absorption and emission. Information can therefore be gained while conventional radiative exchange is extremely small. The experiment consequently does not establish a strict identity between information and emitted atomic radiation. To transform this conceptual tension into empirical progress, the article pro- poses an experimental program in which Shannon information gain, atom–field mutual information, atomic phase shifts, field-energy changes, emitted radiative energy, and environmental exchange are separately quantified. A TO-specific physical prediction would require a measurable quantity or residual not already predicted by standard quantum electrodynamics. The analysis further examines possible relations to TO’s phenomenic elements, Inductor Effects, cosmogonic theorem, and cosmological Eras while avoiding unsupported cosmological extrapolation from a laboratory experiment. In dialogue with Heisenberg, Einstein, Bohm, Prigogine, Kuhn, Penrose, Zurek, Aspect, Planck, LIGO/Virgo, JWST observations, and the foundational and recent literature of TO, the study concludes that Guerlin et al. constitute a particularly valuable empirical interlocutor for the relational and informational dimensions of TO but do not provide exclusive confirmation of the theory. The final assessment places the article at 8.5/10 on a scale measuring the substantive degree of dialogue with the Theory of Objectivity. Keywords: Theory of Objectivity; quantum non-demolition measurement; photon counting; cavity quantum electrodynamics; Rydberg atoms; quantum information; relational observation; field-state collapse; Fock states; modal ontology; information; atomic radiation; Inductor Effects.

Sep 6, 20260 citations

Quantum Non-Demolition Photon Counting in a 2d Rydberg Atom Array

Christopher Fechisin, Kunal Sharma, Przemysław Bienias +4 more

Rydberg arrays merge the collective behavior of ordered atomic arrays with the controllability and optical nonlinearities of Rydberg systems, resulting in a powerful platform for realizing photonic many-body physics. As an application of this platform, we propose a protocol for quantum non-demolition (QND) photon counting. Our protocol involves photon storage in the Rydberg array, an observation phase consisting of a series of Rabi flops to a Rydberg state and measurements, and retrieval of the stored photons. The Rabi frequency experiences a $\sqrt{n}$ collective enhancement, where $n$ is the number of photons stored in the array. Projectively measuring the presence or absence of a Rydberg excitation after oscillating for some time is thus a weak measurement of photon number. We demonstrate that the photon counting protocol can be used to distill Fock states from arbitrary pure or mixed initial states and to perform photonic state discrimination. We confirm that the protocol still works in the presence of experimentally realistic noise.Rydberg arrays merge the collective behavior of ordered atomic arrays with the controllability and optical nonlinearities of Rydberg systems, resulting in a powerful platform for realizing photonic many-body physics. As an application of this platform, we propose a protocol for quantum non-demolition (QND) photon counting. Our protocol involves photon storage in the Rydberg array, an observation phase consisting of a series of Rabi flops to a Rydberg state and measurements, and retrieval of the stored photons. The Rabi frequency experiences a $\sqrt{n}$ collective enhancement, where $n$ is the number of photons stored in the array. Projectively measuring the presence or absence of a Rydberg excitation after oscillating for some time is thus a weak measurement of photon number. We demonstrate that the photon counting protocol can be used to distill Fock states from arbitrary pure or mixed initial states and to perform photonic state discrimination. We confirm that the protocol still works in the presence of experimentally realistic noise.

arXiv:2210.10798Oct 19, 20220 citations

QUANTUM NON-DEMOLITION PHOTON COUNTING AND TIME-RESOLVED RECONSTRUCTION OF NON-CLASSICAL FIELD STATES IN A CAVITY

S. Haroche, S. Deléglise, C. Sayrin +7 more

International Conference on Atomic Physics (ICAP)Mar 1, 20090 citations

\sqrt{n}

collective enhancement, where

n

is the number of photons stored in the array. Projectively measuring the presence or absence of a Rydberg excitation after oscillating for some time is thus a weak measurement of photon number. We demonstrate that the photon counting protocol can be used to distill Fock states from arbitrary pure or mixed initial states and to perform photonic state discrimination. We confirm that the protocol still works in the presence of experimentally realistic noise.