arXiv subjects

Edwin Pedrozo-Peñafiel

Publications and source records attributed to Edwin Pedrozo-Peñafiel.

13 recordsLinked to original sources

arXiv2026

Time-Reversal and Reversible Dynamics in Cavity QED for Quantum Metrology

Quantum-enhanced metrology relies on entanglement to achieve sensitivities beyond the standard quantum limit. While remarkable progress has been made in generating highly entangled many-body states, extracting their metrological advantage remains a central challenge because the encoded information is often inaccessible to realistic measurements. A key development of the past decade has been the realization that many-body interactions can play a dual role: they can be used not only to generate entanglement, but also to decode it. This idea underlies interaction-based readout and time-reversal protocols, in which controlled non-linear dynamics transform weakly encoded signals into experimentally accessible observables. Cavity quantum electrodynamics (QED) provides a particularly powerful setting for these approaches because it combines collective enhancement, tunable interactions, and controllable reversibility within a single platform. In this review, we discuss the emergence of time-reversal protocols in cavity QED, from their conceptual roots in Loschmidt echoes to modern implementations of signal amplification through a time-reversed interaction (SATIN), scrambling-enhanced metrology, and more general interaction-based readout schemes. We examine the physical mechanisms that enable reversible many-body dynamics, review key experimental demonstrations, and discuss future directions involving complex entangled states, nonlinear decoding, and emerging quantum platforms. Together, these developments suggest that the ability to decode quantum information may become as important as the ability to generate it, establishing reversible many-body dynamics as a central resource for quantum-enhanced sensing.

quant-ph↗

arXiv2026

Non-destructive cavity readout of molecules for precision measurements

We propose a non-destructive method to measure the population of molecules in a selected rotational-hyperfine state by coupling them to a high-finesse optical cavity. In contrast to traditional techniques, our approach enables fast (less than 1 ms) repeated measurements with reduced heating and losses, and with precision below the standard quantum limit. The method is particularly advantageous for radioactive molecules, systems of high interest for symmetry violation searches, for which production and sample size are limited, and repeated interrogation is essential for improved sensitivity.

physics.atom-ph↗

arXiv2025

Quantum-amplified global-phase spectroscopy on an optical clock transition

Optical lattice clocks (OLCs) are at the forefront of precision metrology, operating near a standard quantum limit (SQL) set by quantum noise. Harnessing quantum entanglement offers a promising route to surpass this limit, yet there remain practical roadblocks concerning scalability and measurement resolution requirements. Here, we adapt the holonomic quantum-gate concept to develop a novel Rabi-type "global-phase spectroscopy" (GPS) that utilizes the detuning-sensitive global Aharanov-Anandan phase. With this approach, we are able to demonstrate quantum-amplified time-reversal spectroscopy in an OLC that achieves 2.4(7) dB metrological gain without subtracting the laser noise, and 4.0(8) dB improvement in laser noise sensitivity beyond the SQL. We further introduce rotary echo to protect the dynamics from inhomogeneities in light-atom coupling and implement a laser-noise-canceling differential measurement through symmetric phase encoding in two nuclear spin states. Our technique is not limited by measurement resolution, scales easily owing to the global nature of entangling interaction, and exhibits high resilience to typical experimental imperfections. We expect it to be broadly applicable to next-generation atomic clocks and other quantum sensors approaching the fundamental quantum precision limits.

physics.atom-ph↗

arXiv2023

Increased Atom-Cavity Coupling through Cooling-Induced Atomic Reorganization

The strong coupling of atoms to optical cavities can improve optical lattice clocks as the cavity enables metrologically useful collective atomic entanglement and high-fidelity measurement. To this end, it is necessary to cool the ensemble to suppress motional broadening, and advantageous to maximize and homogenize the atom-cavity coupling. We demonstrate resolved Raman sideband cooling via the cavity as a method that can simultaneously achieve both goals. In 200 ms, we cool 171Yb atoms to an average vibration number = 0.23(7) in the tightly binding direction, resulting in 93% optical π-pulse fidelity on the clock transition 1S0 -> 3P0. During cooling, the atoms self-organize into locations with maximal atom-cavity-coupling, which will improve quantum metrology applications.

physics.atom-ph↗

arXiv2023

Improving Metrology with Quantum Scrambling

Quantum scrambling describes the spreading of local information into many degrees of freedom in quantum systems. This provides the conceptual connection among diverse phenomena ranging from thermalizing quantum dynamics to models of black holes. Here we experimentally probe the exponential scrambling of a multi-particle system near a bistable point in phase space and utilize it for entanglement-enhanced metrology. We use a time-reversal protocol to observe a simultaneous exponential growth of both the metrological gain and the out-of-time-order correlator, thereby experimentally verifying the relation between quantum metrology and quantum information scrambling. Our experiments demonstrate that fast-scrambling dynamics capable of exponentially fast entanglement generation are useful for practical metrology, resulting in 6.8(4) dB gain beyond the Standard Quantum Limit.

quant-ph↗

arXiv2022

Entanglement-Enhanced Optical Atomic Clocks

Recent developments in atomic physics have enabled the experimental generation of many-body entangled states to boost the performance of quantum sensors beyond the Standard Quantum Limit (SQL). This limit is imposed by the inherent projection noise of a quantum measurement. In this perspective article, we describe the commonly used experimental methods to create many-body entangled states to operate quantum sensors beyond the SQL. In particular, we focus on the potential of applying quantum entanglement to state-of-the-art optical atomic clocks. In addition, we present recently developed time-reversal protocols that make use of complex states with high quantum Fisher information without requiring sub-SQL measurement resolution. We discuss the prospects for reaching near-Heisenberg limited quantum metrology based on such protocols.

quant-ph↗

arXiv2022

Collective Spin-Light and Light-Mediated Spin-Spin Interactions in an Optical Cavity

The interaction between an atomic ensemble and a light mode in a high-finesse optical cavity can easily reach the strong-coupling regime, where quantum effects dominate. In this regime, the interaction can be used to generate both atom-light and atom-atom entanglement. We analyze the dominant effects on the collective atomic state and the light field, and derive a unified approach that can account for atomic entanglement induced both by measurements on the light field, and by ignoring the state of the light field altogether. We present analytical expressions for the entanglement induced by the interaction, and determine the conditions that maximize the entanglement-induced gain over the standard quantum limit in quantum sensors and atomic clocks.

quant-ph↗

arXiv2021

Time-Reversal-Based Quantum Metrology with Many-Body Entangled States

In quantum metrology, entanglement represents a valuable resource that can be used to overcome the Standard Quantum Limit (SQL) that bounds the precision of sensors that operate with independent particles. Measurements beyond the SQL are typically enabled by relatively simple entangled states (squeezed states with Gaussian probability distributions), where quantum noise is redistributed between different quadratures. However, due to both fundamental limitations and the finite measurement resolution achieved in practice, sensors based on squeezed states typically operate far from the true fundamental limit of quantum metrology, the Heisenberg Limit. Here, by implementing an effective time-reversal protocol through a controlled sign change in an optically engineered many-body Hamiltonian, we demonstrate atomic-sensor performance with non-Gaussian states beyond the limitations of spin squeezing, and without the requirement of extreme measurement resolution. Using a system of 350 neutral $^{171}$Yb atoms, this signal amplification through time-reversed interaction (SATIN) protocol achieves the largest sensitivity improvement beyond the SQL ($11.8 \pm 0.5$~dB) demonstrated in any interferometer to date. Furthermore, we demonstrate a precision improving in proportion to the particle number (Heisenberg scaling), at fixed distance of 12.6~dB from the Heisenberg Limit. These results pave the way for quantum metrology using complex entangled states, with potential broad impact in science and technology. Potential applications include searches for dark matter and for physics beyond the standard model, tests of the fundamental laws of physics, timekeeping, and geodesy.

quant-ph↗

arXiv2020

Trapping $^{171}$Yb Atoms into a One-Dimensional Optical Lattice with a Small Waist

In most experiments with atoms trapped in optical lattices, the transverse size of the optical lattice beams is on the order of tens of micrometers, and loading many atoms into smaller optical lattices has not been carefully investigated. We report trapping 1500 $^{171}$Yb atoms in a one-dimensional optical lattice generated by a narrow cavity mode at a distance of 0.14 mm from a mirror surface. The simplest approach of loading atoms from a mirror magneto-optical trap overlapped with the cavity mode allows the adjustment of the loading position by tuning a uniform bias magnetic field. The number of atoms trapped in the optical lattice exhibits two local maxima for different lattice depths, with a global maximum in the deeper lattice. These results open a way to quantum mechanical manipulation of atoms based on strong interaction with a tightly focused light field.

physics.atom-ph↗

arXiv2020

Entanglement-Enhanced Optical Atomic Clock

State-of-the-art atomic clocks are based on the precise detection of the energy difference between two atomic levels, measured as a quantum phase accumulated in a given time interval. Optical-lattice clocks (OLCs) now operate at or near the standard quantum limit (SQL) that arises from the quantum noise associated with discrete measurement outcomes. While performance beyond the SQL has been achieved in microwave clocks and other atomic sensors by engineering quantum correlations (entanglement) between the atoms, the generation of entanglement on an optical-clock transition and operation of such a clock beyond the SQL represent major goals in quantum metrology that have never been demonstrated. Here we report creation of a many-atom entangled state on an optical transition, and demonstrate an OLC with an Allan deviation below the SQL. We report a metrological gain of $4.4^{+0.6}_{-0.4}$ dB over the SQL using an ensemble consisting of a few hundred 171Yb atoms, allowing us to reach a given stability $2.8{\pm}0.3$ times faster than the same clock operated at the SQL. Our results should be readily applicable to other systems, thus enabling further advances in timekeeping precision and accuracy. Entanglement-enhanced OLCs will have many scientific and technological applications, including precision tests of the fundamental laws of physics, geodesy, or gravitational wave detection.

quant-ph↗

arXiv2019

Robust kHz-linewidth distributed Bragg reflector laser with optoelectronic feedback

We demonstrate a combination of optical and electronic feedback that significantly narrows the linewidth of distributed Bragg reflector lasers (DBRs). We use optical feedback from a long external fiber path to reduce the high-frequency noise of the laser. An electro-optic modulator placed inside the optical feedback path allows us to apply electronic feedback to the laser frequency with very large bandwidth, enabling robust and stable locking to a reference cavity that suppresses low-frequency components of laser noise. The combination of optical and electronic feedback allows us to significantly lower the frequency noise power spectral density of the laser across all frequencies and narrow its linewidth from a free-running value of 1.1 MHz to a stabilized value of 1.9 kHz, limited by the detection system resolution. This approach enables the construction of robust lasers with sub-kHz linewidth based on DBRs across a broad range of wavelengths.

physics.optics↗

arXiv2019

Near-Unitary Spin Squeezing in $^{171}$Yb

Spin squeezing can improve atomic precision measurements beyond the standard quantum limit (SQL), and unitary spin squeezing is essential for improving atomic clocks. We report substantial and nearly unitary spin squeezing in $^{171}$Yb, an optical lattice clock atom. The collective nuclear spin of $\sim 10^3$ atoms is squeezed by cavity feedback, using light detuned from the system's resonances to attain unitarity. The observed precision gain over the SQL is limited by state readout to 6.5(4) dB, while the generated states offer a gain of 12.9(6) dB, limited by the curvature of the Bloch sphere. Using a squeezed state within 30% of unitarity, we demonstrate an interferometer that improves the averaging time over the SQL by a factor of 3.7(2). In the future, the squeezing can be simply transferred onto the optical clock transition of $^{171}$Yb.

physics.atom-ph↗

arXiv2019

Geometrically asymmetric optical cavity for strong atom-photon coupling

Optical cavities are widely used to enhance the interaction between atoms and light. Typical designs using a geometrically symmetric structure in the near-concentric regime face a tradeoff between mechanical stability and high single-atom cooperativity. To overcome this limitation, we design and implement a geometrically asymmetric standing-wave cavity. This structure, with mirrors of very different radii of curvature, allows strong atom-light coupling while exhibiting good stability against misalignment. We observe effective cooperativities ranging from $η_{\rm eff}=10$ to $η_{\rm eff}=0.2$ by shifting the location of the atoms in the cavity mode. By loading $^{171}$Yb atoms directly from a mirror magneto-optical trap into a one-dimensional optical lattice along the cavity mode, we produce atomic ensembles with collective cooperativities up to $Nη=2\times 10^4$. This system opens a way to preparing spin squeezing for an optical lattice clock and to accessing a range of nonclassical collective states.

physics.atom-ph↗