arXiv subjects

T. Zanon-Willette

Publications and source records attributed to T. Zanon-Willette.

17 recordsLinked to original sources

arXiv2026

Fault-tolerant hyper-Ramsey spectroscopy of ultra-narrow clock transitions with dynamical decoupling

A probe laser field that interrogates an atomic transition also shifts it. Although Hyper-Ramsey (HR) spectroscopy was developed to mitigate these light-induced frequency shifts, the technique remains sensitive to probe intensity fluctuations. In this work, we introduce a novel class of dynamically decoupled hyper-Ramsey (DDHR) sequences that utilize a modified refocusing pulse to effectively eliminate this residual sensitivity. This three-pulse interferometric protocol significantly enhances the contrast of quantum interference fringes while providing robust immunity against probe-induced frequency shifts, even in the presence of external field inhomogeneities. We experimentally validate both HR and DDHR protocols on the NQCH and \textcolor{blue}{IQM} superconducting quantum processor, demonstrating an error scaling that is rigorously consistent with theoretical simulations of the optical clock regime. DDHR spectroscopy yields superior suppression of residual probe-induced frequency shifts compared to the standard HR scheme under probe amplitude fluctuation and decoherence. Furthermore, we demonstrate that the implementation of composite refocusing pulses, derived from a Pascal binomial tree architecture, gives substantial resilience against technical pulse area imperfections. Ultimately, fault-tolerant, dynamically decoupled hyper-clocks will offer a promising experimental platform for the evaluation of advanced, NMR-inspired DDHR sequences of multiple refocusing pulses holding significant potential for high-precision matter/antimatter quantum sensing and rigorous tests of fundamental physics within harsh electromagnetic environments.

physics.atom-ph↗

arXiv2023

Theory of nonlinear sub-Doppler laser spectroscopy taking into account atomic-motion-induced density-dependent effects in a gas

We develop a field-nonlinear theory of sub-Doppler spectroscopy in a gas of two-level atoms, based on a self-consistent solution of the Maxwell-Bloch equations in the mean field and single-atom density matrix approximations. This makes it possible to correctly take into account the effects caused by the free motion of atoms in a gas, which lead to a nonlinear dependence of the spectroscopic signal on the atomic density even in the absent of a direct interatomic interaction (e.g., dipole-dipole interaction). Within the framework of this approach, analytical expressions for the light field were obtained for an arbitrary number of resonant waves and arbitrary optical thickness of a gas medium. Sub-Doppler spectroscopy in the transmission signal for two counterpropagating and co-propagating waves has been studied in detail. A previously unknown red shift of a narrow sub-Doppler resonance is predicted in a counterpropagating waves scheme, when the frequency of one wave is fixed and the frequency of the other wave is varied. The magnitude of this shift depends on the atomic density and can be more than an order of magnitude greater than the known shift from the interatomic dipole-dipole interaction (Lorentz-Lorenz shift). The found effects, caused by the free motion of atoms, require a significant revision of the existing picture of spectroscopic effects depending on the density of atoms in a gas. Apart of fundamental aspect, obtained results are important for precision laser spectroscopy and optical atomic clocks.

physics.atom-ph↗

arXiv2023

Engineering quantum control with twisted-light fields induced optical transitions

A novel form of quantum control is proposed by applying twisted-light also known as optical vortex beams to drive ultra-narrow atomic transitions in neutral Ca, Mg, Yb, Sr, Hg and Cd bosonic isotopes. This innovative all-optical spectroscopic method introduces spatially tailored electric and magnetic fields to fully rewrite atomic selection rules reducing simultaneously probe-induced frequency-shifts and additional action of external ac and dc field distortions. A twisted-light focused probe beam produces strong longitudinal electric and magnetic fields along the laser propagation axis which opens the 1S0-3P0 doubly forbidden clock transition with a high E1M1 two-photon excitation rate. This long-lived clock transition is thus immune to nonscalar electromagnetic perturbations. Zeeman components of the M2 magnetic quadrupole 1S0-3P2 transition considered for quantum computation and simulation are now selectively driven by transverse or longitudinal field gradients with vanishing electric fields. These field gradients are manipulated by the mutual action of orbital and spin angular momentum of the light beam and are used in presence of tunable vector and tensor polarizabilities. A combination of these two different twisted-light induced clock transitions within a single quantum system, at the same magic wavelength and in presence of a common thermal environment significantly reduces systematic uncertainties. Furthermore, it generates an optical synthetic frequency which efficiently limits the blackbody radiation shift and its variations at room temperature. Engineering light-matter interaction by optical vortices will benefit to experimental atomic and molecular platforms targeting an optimal coherent control of quantum states, reliant quantum simulation, novel approach to atomic interferometry and precision tests of fundamental theories in physics and high-accuracy optical metrology.

physics.atom-ph↗

arXiv2022

SU(2) hyper-clocks: quantum engineering of spinor interferences for time and frequency metrology

In 1949, Ramsey's method of separated oscillating fields was elaborated boosting over many decades metrological performances of atomic clocks and becoming the standard technique for very high precision spectroscopic measurements. A generalization of this interferometric method is presented replacing the two single coherent excitations by arbitrary composite laser pulses. The rotation of the state vector of a two-level system under the effect of a single pulse is described using the Pauli matrices basis of the SU(2) group. It is then generalized to multiple excitation pulses by a recursive Euler-Rodrigues-Gibbs algorithm describing a composition of rotations with different rotation axes. A general analytical formula for the phase-shift associated with the clock's interferometric signal is derived. As illustrations, hyper-clocks based on three-pulse and five-pulse interrogation protocols are studied and shown to exhibit nonlinear cubic and quintic sensitivities to residual probe-induced light-shifts. The presented formalism is well suited to optimize composite phase-shifts produced by tailored quantum algorithms in order to design a new generation of optical frequency standards and robust engineering control of atomic interferences in AMO physics with cold matter and anti-matter.

physics.atom-ph↗

arXiv2022

Generalized hyper-Ramsey-Bordé matter-wave interferometry: quantum engineering of robust atomic sensors with composite pulses

A new class of atomic interferences using ultra-narrow optical transitions are pushing quantum engineering control to a very high level of precision for a next generation of sensors and quantum gate operations. In such context, we propose a new quantum engineering approach to Ramsey-Bordé interferometry introducing multiple composite laser pulses with tailored pulse duration, Rabi field amplitude, frequency detuning and laser phase-step. We explore quantum metrology with hyper-Ramsey and hyper-Hahn-Ramsey clocks below the $10^-18$ level of fractional accuracy by a fine tuning control of light excitation parameters leading to spinor interferences protected against light-shift coupled to laser-probe field variation. We review cooperative composite pulse protocols to generate robust Ramsey-Bordé, Mach-Zehnder and double-loop atomic sensors shielded against measurement distortion related to Doppler-shifts and light-shifts coupled to pulse area errors. Fault-tolerant auto-balanced hyper-interferometers are introduced eliminating several technical laser pulse defects that can occur during the entire probing interrogation protocol. Quantum sensors with composite pulses and ultra-cold atomic sources should offer a new level of high accuracy in detection of acceleration and rotation inducing phase-shifts, a strong improvement in tests of fundamental physics with hyper-clocks while paving the way to a new conception of atomic interferometers tracking space-time gravitational waves with a very high sensitivity.

physics.atom-ph↗

arXiv2022

Hyper Ramsey-Bordé matter-wave interferometry for robust quantum sensors

A new generation of atomic sensors using ultra-narrow optical clock transitions and composite pulses are pushing quantum engineering control to a very high level of precision for applied and fundamental physics. Here, we propose a new version of Ramsey-Bordé interferometry introducing arbitrary composite laser pulses with tailored pulse duration, Rabi field, detuning and phase-steps. We explore quantum metrology below the $10^{-18}$ level of fractional accuracy by a fine tuning control of light excitation parameters protecting ultra-narrow optical clock transitions against residual light-shift coupled to laser-probe field fluctuation. We present, for the first time, new developments for robust hyper Ramsey-Bordé and Mach-Zehnder interferometers, where we protect wavepacket interferences against distortion on frequency or phase measurement related to residual Doppler effects and light-shifts coupled to a pulse area error. Quantum matter-wave sensors with composite pulses and ultra-cold sources will offer detection of inertial effects inducing phase-shifts with better accuracy, to generate hyper-robust optical clocks and improving tests of fundamental physics, to realize a new class of atomic interferometers tracking space-time gravitational waves with a very high sensitivity.

physics.atom-ph↗

arXiv2021

Harmonic dual dressing of spin one-half systems

Controlled modifications of the quantum magnetic response are produced in dressed systems by a high frequency, strong and not-resonant electromagnetic field. This quantum control is greatly enhanced and enriched by the harmonic, commensurable and orthogonally oriented dual dressing theoretically discussed here. The secondary field enables a fine tuning of the qubit response, with control parameters amplitude, harmonic content, spatial orientation and phase relation. Our analysis is based on a perturbative approach and includes few numerical solutions. The long-time dynamics is described in terms of an anisotropic effective static magnetic field representing the handle for the system full engineering. Through a low-order harmonic mixing the bichromatic driving generates a rectified static field acting on the spin. The Zeeman response becomes anisotropic in a triaxial geometry and includes a quadratic contribution. Our dressing increases the two-level energy splitting, improving the spin detection sensitivity. On the low field direction it compensates the static fields applied in different geometries. A resonant spin exchange between two species having very different magnetic response as electron and nucleus is allowed by the dressing. The spin temporal evolution includes a micromotion at harmonics of the driving frequency whose role in the spin detection is examined and can be exploited in quantum information. The results presented here lay a foundation for additional applications to be harnessed in quantum simulations.

quant-ph↗

arXiv2019

Generalized Hyper-Ramsey spectroscopy in an optically dense medium

In this work, the peculiarities of Ramsey resonance and its sensitivity to the light shift from an optically dense medium of cold atoms are investigated. We considered different composite pulse protocols for clock spectroscopy such as hyper-Ramsey, modified and generalized hyper-Ramsey schemes. Shapes of resonances and error signals changes significantly due to the processes of absorption and dispersion in the atomic medium. The dependence of the position of the central fringe resonance with a residual uncompensated light shift of the atomic transition is theoretically studied when taking into account the attenuation of the radiation intensity in the medium. The change in pulses area of the hyper-Ramsey protocol allows us to suppress the sensitivity of the clock resonance position to the residual light shift for a certain length of the medium. It is shown that using a combination of generalized hyper- Ramsey error signals allows us to suppress the sensitivity to the light shift for any length of the medium. Also we analyzed the effect of spontaneous decay of high atomic state on the light shift sensitivity of the composite pulses schemes.

physics.atom-ph↗

arXiv2018

Combined error signal in Ramsey spectroscopy of clock transitions

We have developed a universal method to form the reference signal for the stabilization of arbitrary atomic clocks based on Ramsey spectroscopy. Our approach uses an interrogation scheme of the atomic system with two different Ramsey periods and a specially constructed combined error signal (CES) computed by subtracting two error signals with the appropriate calibration factor. CES spectroscopy allows for perfect elimination of probe-induced light shifts and does not suffer from the effects of relaxation, time-dependent pulse fluctuations and phase-jump modulation errors and other imperfections of the interrogation procedure. The method is simpler than recently developed auto-balanced Ramsey spectroscopy techniques [Ch. Sanner, et al., Phys. Rev. Lett. 120, 053602 (2018); V. I. Yudin, et al., Phys. Rev. Appl. 9, 054034 (2018)], because it uses a single error signal that feeds back on the clock frequency. CES universal technique can be applied to many applications of precision spectroscopy.

physics.atom-ph↗

arXiv2018

Non-linear frequency-sweep correction of tunable electromagnetic sources

Tunable electromagnetic sources, such as voltage controlled oscillators (VCO), micro electromechanical systems (MEMS) or diode lasers are often required to be linear during frequency-sweep modulation. In many cases, it might also be sufficient that the degree of the non-linearity can be well controlled. Without further efforts, these conditions are rarely achieved using free running sources. Based on a pre-distortion voltage ramp, we develop in this letter a simple and universal method that minimizes the non-linear frequency response of tunable electromagnetic sources. Using a current-driven Quantum Cascade Laser (QCL) as an example, we demonstrate that the non-linearity can easily be reduced by a factor of ten when using a single distortion parameter $γ$. In the investigation of the IR absorption spectrum of ozone at 10\,$μ$m, an even better reduction of the frequency scale error by two orders of magnitude is obtained by using the pre-distortion method to generate an essentially purely quadratic sweep frequency dependency which can be inverted easily to retrieve precise molecular line positions. After having tested our method on a variety of electromagnetic sources, we anticipate a wide range of applications in a variety of fields.

physics.atom-ph↗

arXiv2018

Generalized auto-balanced Ramsey spectroscopy of clock transitions

When performing precision measurements, the quantity being measured is often perturbed by the measurement process itself. This includes precision frequency measurements for atomic clock applications carried out with Ramsey spectroscopy. With the aim of eliminating probe-induced perturbations, a method of generalized auto-balanced Ramsey spectroscopy (GABRS) is presented and rigorously substantiated. Here, the usual local oscillator frequency control loop is augmented with a second control loop derived from secondary Ramsey sequences interspersed with the primary sequences and with a different Ramsey period. This second loop feeds back to a secondary clock variable and ultimately compensates for the perturbation of the clock frequency caused by the measurements in the first loop. We show that such a two-loop scheme can lead to perfect compensation of measurement-induced light shifts and does not suffer from the effects of relaxation, time-dependent pulse fluctuations and phase-jump modulation errors that are typical of other hyper-Ramsey schemes. Several variants of GABRS are explored based on different secondary variables including added relative phase shifts between Ramsey pulses, external frequency-step compensation, and variable second-pulse duration. We demonstrate that a universal anti-symmetric error signal, and hence perfect compensation at finite modulation amplitude, is generated only if an additional frequency-step applied during both Ramsey pulses is used as the concomitant variable parameter. This universal technique can be applied to the fields of atomic clocks, high-resolution molecular spectroscopy, magnetically induced and two-photon probing schemes, Ramsey-type mass spectrometry, and to the field of precision measurements. Some variants of GABRS can also be applied for rf atomic clocks using CPT-based Ramsey spectroscopy of the two-photon dark resonance.

physics.atom-ph↗

arXiv2017

Universal ultra-robust interrogation protocol with zero probe-field-induced frequency shift for quantum clocks and high-accuracy spectroscopy

Optical clock interrogation protocols, based on laser-pulse spectroscopy, are suffering from probe-induced frequency shifts and their variations induced by laser power. Original Hyper-Ramsey probing scheme, which was proposed to alleviate those issues, does not fully eliminate the shift, especially when decoherence and relaxation by spontaneous emission or collisions are present. We propose to solve the fundamental problem of frequency shifts induced by laser probe by deriving the exact canonical form of a multi-pulse generalized Hyper-Ramsey (GHR) resonance, including decoherence and relaxation. We present a universal interrogation protocol based on composite laser-pulses spectroscopy with phase-modulation eliminating probe-induced frequency shifts at all orders in presence of various dissipative processes. Unlike frequency shifts extrapolation-based methods, a universal interrogation protocol based on $\pmπ/4$ and $\pm3π/4$ phase-modulated resonances is proposed which does not compromise the stability of the optical clock while maintaining an ultra-robust error signal gradient in presence of substantial uncompensated ac Stark-shifts. Such a scheme can be implemented in two flavours: either by inverting clock state initialization or by pulse order reversal even without a perfect quantum state initialization. This universal interrogation protocol can be applied to atomic, molecular and nuclear frequency metrology, mass spectrometry and to the field of precision spectroscopy. It might be designed using magic-wave induced transitions, two-photon excitation and magnetically-induced spectroscopy or it might even be implemented with quantum logic gate circuit and qubit entanglement.

physics.atom-ph↗

arXiv2016

Synthetic Frequency Protocol in the Ramsey Spectroscopy of Clock Transitions

We develop an universal method to significantly suppress probe-induced shifts in any types of atomic clocks using the Ramsey spectroscopy. Our approach is based on adaptation of the synthetic frequency concept [V. I. Yudin, et al., Phys. Rev. Lett. 107, 030801 (2011)] (previously developed for BBR shift suppression) to the Ramsey spectroscopy with the use of interrogations for different dark time intervals. Universality of the method consists in arbitrariness of the possible Ramsey schemes. However, most extremal results are obtained in combination with so-called hyper-Ramsey spectroscopy [V. I. Yudin, et al., Phys. Rev. A 82, 011804(R) (2010)]. In the latter case, the probe-induced frequency shifts can be suppressed considerably below a fractional level of 10$^{-18}$ practically for any optical atomic clocks, where this shift previously was metrologically significant. The main advantage of our method in comparison with other radical hyper-Ramsey approaches [R. Hobson, et al., Phys. Rev. A 93, 010501(R) (2016); T. Zanon-Willette, et al., Phys. Rev. A 93, 042506 (2016)] consist in much greater efficiency and resistibility in the presence of decoherentization.

physics.atom-ph↗

arXiv2016

Composite pulses in Hyper-Ramsey spectroscopy for the next generation of atomic clocks

The next generation of atomic frequency standards based on an ensemble of neutral atoms or a single-ion will provide very stringent tests in metrology, applied and fundamental physics requiring a new step in very precise control of external systematic corrections. In the proceedings of the 8th Symposium on Frequency Standards and Metrology, we present a generalization of the recent Hyper-Ramsey spectroscopy with separated oscillating fields using composites pulses in order to suppress field frequency shifts induced by the interrogation laser itself. Sequences of laser pulses including specific selection of phases, frequency detunings and durations are elaborated to generate spectroscopic signals with a strong reduction of the light-shift perturbation by off resonant states. New optical clocks based on weakly allowed or completely forbidden transitions in atoms, ions, molecules and nuclei will benefit from these generalized Ramsey schemes to reach relative accuracies well below the 10$^{-18}$ level.

physics.atom-ph↗

arXiv2015

Generalized Hyper-Ramsey Resonance with separated oscillating fields

An exact generalization of the Ramsey transition probability is derived to improve ultra-high precision measurement and quantum state engineering when a particle is subjected to independently-tailored separated oscillating fields. The phase-shift accumulated at the end of the interrogation scheme offering high-level control of quantum states throughout various laser parameters conditions. The Generalized Hyper-Ramsey Resonance based on independent manipulation of interaction time, field amplitude, phase and frequency detuning is presented to increase the performance of next generation of atomic, molecular and nuclear clocks, to upgrade high resolution frequency measurement in Penning trap mass spectrometry and for a better control of light induced frequency shifts in matter wave interferometers or quantum information processing.

physics.atom-ph↗

arXiv2014

Quantum engineering of atomic phase-shifts in optical clocks

Quantum engineering of time-separated Raman laser pulses in three-level systems is presented to produce an ultra-narrow optical transition in bosonic alkali-earth clocks free from light shifts and with a significantly reduced sensitivity to laser parameter fluctuations. Based on a quantum artificial complex-wave-function analytical model, and supported by a full density matrix simulation including a possible residual effect of spontaneous emission from the intermediate state, atomic phase-shifts associated to Ramsey and Hyper-Ramsey two-photon spectroscopy in optical clocks are derived. Various common-mode Raman frequency detunings are found where the frequency shifts from off-resonant states are canceled, while strongly reducing their uncertainties at the 10$^{-18}$ level of accuracy.

physics.atom-ph↗

arXiv2006

Dynamic cancellation of ac Stark shift for pulsed EIT/Raman optical lattice clocks

We propose a combination of Electromagnetically Induced Transparency (EIT)/Raman and pulsed spectroscopy techniques to accurately cancel frequency shifts arising from EIT fields in forbidden optical lattice clock transitions of alkaline earth atoms. Time-separated laser pulses are designed to trap atoms in coherent superpositions while eliminating off-resonance ac Stark contributions at particular laser detunings from the intermediate excited state. The scheme achieves efficient population transfer up to 60% with potential inaccuracy $<$ $10^{-17}$. Cancellation of external light shifts determined by a density matrix approach is confirmed by a complex wave-function formalism, sufficient at the mHz accuracy, under low field strengths or short interaction times.

physics.atom-ph↗