In this work, an interactive system composed of a V-type atom and a dissipative single-mode cavity is considered and the atomic quantum coherences are investigated under parameters including spontaneously generated interference (SGI), cavity-environment coupling, weak measurement and its reversal, and detuning between the atom and the cavity. The results indicate that strong coupling can induce coherence sudden death (CSD) and coherence sudden birth (CSB), while the non-zero SGI parameter only induces CSB. Detuning, however, may avoid both CSD and CSB. Moreover, detuning and weak measurement reversal can very effectively protect quantum coherence, while the SGI parameter, weak measurement, and strong coupling can accelerate its attenuation. The SGI parameter, detuning, weak measurement reversal, and strong coupling all promote the generation of coherence, whereas weak measurement alone can suppress it. In particular, the maximal coherent state can be very effectively protected and the coherent state can be prepared if all parameters are selected appropriately. Physical interpretations are also provided for these results.

Controlling the coupling between different degrees of freedom in many-body systems is a powerful technique for engineering novel phases of matter. We create a bilayer system of two-dimensional (2D) ultracold Bose gases and demonstrate the controlled generation of bulk coherence through tunable interlayer Josephson coupling. We probe the resulting correlation properties of both phase modes of the bilayer system: the symmetric phase mode is studied via a noise-correlation method, while the antisymmetric phase fluctuations are directly captured by matter-wave interferometry. The measured correlation functions for both of these modes exhibit a crossover from short-range to quasi-long-range order above a coupling-dependent critical point, thus providing direct evidence of bilayer superfluidity mediated by interlayer coupling. We map out the phase diagram and interpret it with renormalization-group theory and Monte Carlo simulations. Additionally, we elucidate the underlying mechanism through the observation of suppressed vortex excitations in the antisymmetric mode.

Abstract Advancing quantum technologies necessitates an in-depth exploration of how operations generate quantum resources and respond to noise. Crucial are gates generating quantum coherence and the challenge of mitigating gate dephasing noise. Precisely, we study the dephasing noise that reduces the coherence-generating power of quantum gates, its simulation, and critical factors. Our primary contribution lies in a theorem characterizing the full set of dephasing noises in gates, adaptable to the simulation by any predefined operation set. In particular, we apply our result to quantify the the memory adaptability required for a dephasing noise to arise. Furthermore, we analytically calculate the quantifier for gates acting on qubit systems, thereby fully characterizing this scenario. Next, we show how our results reveal the structure of non-trivial dephasing noise affecting qubit gates and apply them to experimental data, conclusively demonstrating the existence of a gate's dephasing noise, which is irreducible to dephasing of either input or output states. Finally, we show how our study contributes to addressing an open question in the resource theory of coherence generation.

Dynamic Nuclear Polarization (DNP) is transforming nuclear magnetic resonance and MRI by significantly enhancing sensitivity through the transfer of polarization from electron spins to nuclear spins via microwave irradiation. However, the use of monochromatic continuous-wave irradiation limits the efficiency of DNP for systems with heterogeneous, broad electron paramagnetic resonance lines. Broadband techniques such as chirp irradiation offer a potential solution, particularly for Solid Effect (SE) DNP in such cases. Despite its widespread use, the role of quantum coherence generated during chirp irradiation remains unclear, even though it is a key factor in determining the maximum achievable DNP efficiency. In this work, we use density matrix formalism to provide a comprehensive understanding of the quantum coherence generated during non-adiabatic passages through electron-nucleus double-quantum (DQ) and zero-quantum (ZQ) SEtransitions and their impact on Integrated Solid Effect (ISE) DNP under chirp irradiation. Our analysis employs fictitious product-operator bases to trace the evolution of electron-nucleus coherence leading to integrated or differentiated SE. We also explore the role of decoherence in maximizing chirped DNP in microwave power or nutation frequency limited scenarios. These findings provide an understanding of the role of coherence generated during pulsed DNP and magic-angle spinning DNP at different temperature ranges. Our results reveal that quantum coherences generated during non-adiabatic passages critically determine whether the chirped DNP process yields ISE or differential solid effect. By analyzing the evolution of the density matrix in DQ and ZQ subspaces, we show how coherence generation and its decay through decoherence play a decisive role in shaping the net DNP enhancement.

Abstract In this study, we have applied the intrinsic decoherence (ID) model of the Milburn equation to investigate the temporal evolution of various quantum resources (steerability, entanglement, and coherence) in the generated dipole-coupled two-qubit states. Einstein–Podolsky–Rosen steering, EOF, and Jensen–Shannon divergence are used to analyze these quantum resources. We consider two dipole-coupled qubit interacting with two spatially separated cavities with nonlinear photonic transitions, filled with a superposition of generalized Barut–Girardello coherent fields. The exploration of steerability, entanglement, and coherence has been carried out by considering the nonlinearity of qubit–cavity interactions, the nonclassicality of the superposition of Barut–Girardello coherent fields, the dipole–dipole coupling, and the ID of qubit–cavity interactions. Our results show that the nonlinearity of qubit–cavity interactions, the initial generalized Barut–Girardello coherent states, and the qubit–cavity detuning significantly enhance the generation of quantum steerability, entanglement, and coherence. The dynamics of entanglement and steerability are consistent with the hierarchy principle. The ID effect reduces the amplitudes and frequencies of the generated quantum resources to their stationary values. It is found that the phenomena of sudden steerability arising and sudden annihilation of entanglement are influenced by the initial non-classicality, dipole coupling, and intrinsic qubit–cavity decoherence. Moreover, the strong decoherence and dipole coupling significantly enhance the steady-state values of steerability, entanglement, and coherence.

Seeded free-electron lasers (FELs) capable of operating at repetition rates up to the MHz level are in high demand for advanced time-resolved spectroscopies, which require both full longitudinal coherence and high average photon flux in the extreme ultraviolet (EUV) and x-ray regimes. However, conventional external-seeding methods require ultraviolet seed lasers with peak powers on the order of 100MW, constraining them to lower repetition rates. Here, we report the first lasing and stable operation of a direct-amplification enabled harmonic generation FEL driven by a weak seed laser with only MW-level peak power. Beginning with an ultraviolet seed laser with only 0.75 μJ pulse energy, we demonstrate its direct amplification to over 10 μJ within an 8-m-long modulator. We observe coherent harmonic generation up to the 12th harmonic of the seed and achieve saturation of the 7th harmonic in the radiator. These results represent a crucial milestone toward the realization of MHz-class, fully coherent EUV and x-ray light sources.

An approach to generating coherent dual-tone microwave signals via an optoelectronic oscillator (OEO) is proposed and demonstrated based on intra-cavity frequency mixing mutual injection locking. In the OEO cavity, two potential oscillation modes are selected by using an electrical dualpassband filter, and they are mixed with each other to generate a differential frequency signal. The self-generated differential frequency signal is then injected back into the OEO cavity to lock the phase relationship between the two oscillation modes via a mutual injection locking process, which breaks the mode competition effect. As a result, a coherent dual-tone microwave signal can be generated. In the experiment, a coherent dual-tone microwave signal with frequencies of 10 GHz and 10.1 GHz is generated, where the side-mode suppression ratios (SMSRs) and the phase noise reach 70 dB and -134.8 dBc/Hz@10 kHz, respectively. This scheme provides a pathway to generate coherent dual-tone microwave signals from an OEO without the requirement of external injection locking.

The ability to comprehend and articulate structured data tables into natural language presents a pivotal yet challenging endeavor for automated systems. While substantial strides have been made in English Table-to-Text Generation (T2T) with the aid of large training datasets and advancements in deep neural networks, comparatively limited attention has been given to low-resourced languages. This paper addresses this gap by introducing the inaugural large-scale dataset for Persian T2T, comprising 128,628 table-text pairs extracted from Persian Wikipedia articles. Detailed statistical analysis and insights are presented to characterize the dataset, providing a comprehensive understanding of the intricacies inherent in Persian T2T tasks. Along with describing the dataset, the study uses this dataset to finetune multilingual pre-trained language models like mT5 and GPT-2 in order to set solid baselines. Evaluation using automated metrics—including BLEU, ROUGE-L, and METEOR—over test data reveals substantial scope for future improvements in modeling. Furthermore, targeted human assessments expose model deficiencies in the coherent generation of lengthy text and interpreting tables, particularly with respect to ambiguous spans. By offering well-matched yet complex table-description pairs and conducting rigorous comparative analyses, this paper establishes a novel benchmark, driving progress in low-resourced conditional text generation and the effectiveness of cross-lingual models. This work not only contributes significantly but also sets the stage for further exploration of this critical yet under-explored task for Persian language processing.

Thermodynamic constraints impose a trade-off between power and efficiency in heat engines, preventing the simultaneous achievement of high power and high efficiency. For classical microscopic engines, explicit inequalities have been discovered, demonstrating the inherent inevitability of this power-efficiency trade-off. However, extensions of these results to quantum engines have so far been limited to cases of slow operation. In this study, we derive a power-efficiency trade-off relation for a paradigmatic quantum engine operating within a finite time, specifically the Otto cycle of a quantum harmonic oscillator. By utilizing a phase-space approach based on quasiprobability representations, we establish a universal trade-off relation applicable to arbitrary time-dependent protocols during the adiabatic processes. Our results reveal that the power of the quantum engine vanishes as the efficiency approaches the quantum-mechanical efficiency bound, which is stricter than the Carnot bound. Furthermore, we identify the conditions under which the upper bound is attained, which indicate maximum power is achieved when the generation of quantum coherence is reduced, and the difference in time durations of the isochoric processes increases. These findings are validated through numerical calculations, which confirm their applicability across various types of protocols for heat engine cycles.

Direct coherent ray generation for path tracing

A beam of relativistic charged particles propagating in a plasma can drive plasma electrons to oscillate and together form a wave whose phase velocity matches the velocity of the driving beam. These plasma waves realize state-of-the-art compact accelerators through plasma wakefield acceleration. Here, we formulate a one-dimensional analytic theory of beam-driven nonlinear plasma waves that is valid for positively and negatively charged particle beams propagating with arbitrary velocity. We find that nonlinear plasma waves can arise within the interior region of the driving beam, with wavelength and amplitude different from those of the plasma wakefield. In contrast to plasma wake waves, the interior waves are robust with respect to driver length variation. Our analytic results can be used to design current and future plasma accelerators, to understand their limitations due to wave breaking, and for applications in coherent light generation in plasma, such as relativistic mirrors formed by breaking plasma waves. Furthermore, we discuss the potential of our results to offer insights into the origin of ultrahigh-energy cosmic rays.

Two-dimensional semiconductors hold great potential as coherent light sources for photonic integrated circuits. However, the conventional integration of two-dimensional materials onto silicon photonics introduces significant structural and optoelectronic drawbacks, hindering the practical realization of coherent photonic circuits. Here, we introduce the concept of a van der Waals photonic integrated circuit, which is a complete on-chip optical system fabricated entirely from a van der Waals heterostructure. By combining multifunctional two-dimensional materials into a single heterostructure, we realize a fully functional photonic circuitry capable of benchtop coherent light generation, propagation, transmission, and modulation via a silicon back gate. The monolithic approach to heterostructure circuitry supports the effective integration of various photonic components based on two-dimensional materials with stable electro-optic interconnections. The coherence of light emission is systematically verified by second-order correlation experiments at room temperature, showing a clear power-dependent transition to a Poissonian regime. Our work establishes a pathway for coherent van der Waals photonics incorporated with standard silicon manufacturing processes.

The pursuit of coherent radiation generation remains a key direction in the advancement of storage ring light sources. Despite the potential of laser modulation in achieving this goal, it leads to a significant decline in the quality of the electron beam. Efforts to mitigate this decline have resulted in the proposal of demodulation schemes. However, implementing modulation and demodulation within the storage ring presents significant challenges due to dynamical and spatial constraints within straight sections. In this study, we propose a straightforward and easily implementable method for achieving reversible laser modulation in a storage ring. Notably, our approach circumvents the need for lengthy straight sections or bypass section. Simulation results show a substantial restoration of beam quality following demodulation. This innovative scheme holds great promise for the realization of high repetition rate coherent storage ring light sources.

In the realization of patterning feature sizes of sub-10 nm in semiconductor devices, it is essential to get new resist design strategies such as inorganic-organic hybrid resist materials for extreme ultraviolet (EUV) lithography. However, it is challenging for fundamental researchers to develop EUV resist materials due to the difficulty in obtaining experimental time for EUV exposure and limited EUV exposure tools, which are very expensive. Recently, we developed ultra-fast coherent EUV system based on high harmonics generation (HHG) and applied to EUV resist evaluation. In this study, the sensitivity of inorganic-organic hybrid resist materials known as metal-oxo clusters was evaluated by using this HHG EUV system. The obtained sensitivities were found to be comparable to the sensitivities obtained by conventional EUV flood exposure tool. It is concluded that the developed coherent HHG EUV system is very useful for sensitivity measurement of EUV resists and developing new EUV resists.

The exponential growth of academic literature presents significant challenges for researchers in conducting comprehensive literature reviews and maintaining current knowledge in their fields. Traditional research methodologies often prove inadequate for processing the vast volumes of information available across multiple databases and repositories (Chen et al., 2024; Rodriguez & Kim, 2023). This study introduces a novel agentic artificial intelligence framework designed to enhance research productivity through intelligent automation of literature discovery and report generation processes. The proposed system employs a dual-agent architecture comprising a specialized Search Agent responsible for multi-database literature discovery and source quality assessment, and a Drafting Agent focused on content analysis, synthesis, and coherent report generation (Thompson & Williams, 2024). Through empirical evaluation involving 150 research tasks across 15 academic domains, our framework demonstrated substantial improvements over traditional research methods: 55% reduction in time requirements (from 18.7 to 8.3 days average), 23% improvement in source coverage (from 77% to 100%), 60% reduction in cost per literature review (from ,847 to ,139), and 28% increase in user satisfaction scores (from 3.2 to 4.1 out of 5.0). The system maintains high quality standards with an average quality score of 4.2/5.0 compared to 3.9/5.0 for traditional methods (Anderson et al., 2024). Domain-specific analysis reveals varying effectiveness, with interdisciplinary research showing the highest performance gains (68% time savings, 91% user satisfaction), followed by STEM disciplines (62% time savings, 94% satisfaction). The framework addresses critical challenges in academic research including information overload, source verification, and synthesis complexity while maintaining scholarly rigor and citation accuracy (Martinez & Lee, 2023). Implementation results demonstrate the practical viability of agentic AI systems in academic research contexts, providing a scalable solution for institutions seeking to enhance research productivity and quality.

Coherent phonons in the Terahertz (THz) regime have gained attention as potential candidates for next-generation high-speed, low-energy information carriers in atomically thin phononic or phonon-integrated on-chip devices. Nevertheless, achieving efficient control of the phonon generation dynamics over THz coherent phonons continues to pose a considerable challenge. In this work, we explore THz coherent phonon generation in exfoliated van der Waals (vdW) flakes of WSe2 on Au (WSe2/Au) and Si (WSe2/Si) by using time-resolved pump-probe spectroscopy. The generation of THz coherent phonons was studied as a function of the WSe2 layer thickness and laser wavelength. Notably, a significant enhancement in THz coherent phonon generation was observed in the WSe2/Au structure, but only within a specific range of WSe2 thicknesses and laser wavelengths. The results from numerical simulations, which consider a self-hybridized optical cavity depending on WSe2 thickness and optical reflectance and Raman spectroscopy measurements, all align well with the time-domain observations of THz coherent phonon generation. We propose that the observed enhancement in THz coherent phonon generation is strongly influenced by light-matter interactions in the WSe2 cavity, a mechanism that may be applicable to a broader range of vdW materials. These findings offer promising insights for the development of THz phononic or phonon-integrated devices.

This work describes the development of an embedded standalone measurement system that monitors the aging of batteries using impedance spectroscopy. The system generates a multisine stimulus that contains the frequency components at which the battery impedance is measured. Coherent generation and sampling is assured, and Goertzel filters, one for each measurement frequency, are updated with each new sample. This architecture reduces memory requirements because the current and voltage of the measured samples are discarded after processing. Aging is monitored, as the system is able to automatically perform complete or partial charge/discharge cycles as well as measurement cycles without requiring user interaction.

In this Letter, we present the experimental observation of squeezed phonon generation in semiconductor germanium (Ge) induced by x-ray excitation. Prior x-ray pump, x-ray probe studies reported coherent longitudinal acoustic phonon generation in insulating oxides like strontium titanate and potassium tantalate. In contrast, such signals were not observed in semiconductors likely due to limited signal-to-noise ratio. Now, with an improved experimental setup, we observe a phonon response in single-crystal germanium. Utilizing x-ray split-delay optics with enhanced stability, we extract the phonon dispersion relation, which shows strong agreement with the calculated transverse acoustic phonon mode. Our results reveal that responses to x-ray excitations in semiconductors are of a similar nature to optical excitations. This suggests that the initial response to x-ray core–hole excitations rapidly diffuses to a non-local excitation, similar to what is observed with optical laser valence excitation on a femtosecond timescale.

Image caption generation, a primary application domain in computer vision and natural language processing, produces text captions of images from deep learning models. The current paper suggests a CNN-LSTM-based system for automatic captioning, where pre-trained convolutional neural networks (CNNs) are employed for image feature extraction and long short-term memory (LSTM) networks for sequential text generation. Inspired by the Flickr8k dataset, the paper emphasizes primary challenges such as vocabulary sparsity, overfitting, and computational complexity. Experimental results achieve BLEU scores of 0.66 or more, exhibiting coherent caption generation and qualitative analysis discloses captioning inefficiencies for complex scenes. The paper also discusses future enhancements such as transformer-based architectures and attention mechanisms to improve caption accuracy and accessibility. The work contributes to improving large-scale human-computer interaction through multimodal AI systems. Caption generation is an important area at the intersection of computer vision and natural language processing, including the generation of descriptive text captions describing images using advanced deep-learning methodologies. Current paper suggests a new approach through a hybrid CNN-LSTM-based system for automatic captioning. This state-of-the-art model employs pre-trained convolutional neural networks (CNNs) for robust image feature extraction to identify and interpret relevant features in an image. These identified features are then fed to long short-term memory (LSTM) networks adept at generating coherent and relevant sequential text based on the visual input. The experimental results revealed excellent BLEU scores of 0.66 or higher, which reflects the model's capacity to generate captions not only accurate but also linguistically sound. Qualitative analysis of the generated captions does call out inefficiencies in handling complicated scenes with more than one element or activity, and it suggests where there is potential for improvement in the future. In the future, the paper foresees potential enhancements, such as the application of transformer-based models and attention, which would significantly improve caption accuracy and user experience for accessibility. Overall, this work contributes to advancing the state of large-scale human-computer interaction by developing sophisticated multimodal AI systems for interpreting and generating human-like text from visual inputs.

We report a coherent tri-frequency microwave signal generation approach using an optoelectronic oscillator (OEO). In the previous literature, the OEO-based schemes can only generate coherent microwave signals with dual frequencies. In this work, we demonstrate that the generation of coherent tri-frequency microwave signals is also possible using an OEO loop. The key component in our scheme is a tri-passband electrical filter, which has a narrow passband in the middle and two wide passbands on both sides. The OEO loop initially oscillates at the central frequency of the narrow passband with a single-tone f1. By injecting a microwave signal, finj, into the OEO loop, down- and up-converted microwave signals at frequencies of f2 = f1 − finj and f3 = f1 + finj, respectively, are generated by frequency mixing in a microwave mixer. The two wide passbands of the electrical filter allow the oscillation of the converted signals at a wide frequency bandwidth by simply tuning the frequency of the injected signal. Moreover, the tri-frequency microwave signals are phase-locked through frequency mixing and mutual injection locking. The proposed scheme is theoretically analyzed and experimentally validated. In the experiments, coherent tri-frequency microwave signals with low phase noise are successfully generated at a fixed frequency of 14 GHz and two tunable frequency ranges from 9 to 12 GHz and from 16 to 19 GHz, respectively.