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The idea of the out-of-time-order correlator (OTOC) has recently emerged in the study of both condensed matter systems and gravitational systems. It not only plays a key role in investigating the holographic duality between a strongly interacting quantum system and a gravitational system, it also diagnoses the chaotic behavior of many-body quantum systems and characterizes information scrambling. Based on OTOCs, three different concepts—quantum chaos, holographic duality, and information scrambling—are found to be intimately related to each other. Despite its theoretical importance, the experimental measurement of the OTOC is quite challenging, and thus far there is no experimental measurement of the OTOC for local operators. Here, we report the measurement of OTOCs of local operators for an Ising spin chain on a nuclear magnetic resonance quantum simulator. We observe that the OTOC behaves differently in the integrable and nonintegrable cases. Based on the recent discovered relationship between OTOCs and the growth of entanglement entropy in the many-body system, we extract the entanglement entropy from the measured OTOCs, which clearly shows that the information entropy oscillates in time for integrable models and scrambles for nonintgrable models. With the measured OTOCs, we also obtain the experimental result of the butterfly velocity, which measures the speed of correlation propagation. Our experiment paves a way for experimentally studying quantum chaos, holographic duality, and information scrambling in many-body quantum systems with quantum simulators.

Processing of digital images is continuously gaining in volume and relevance, with concomitant demands on data storage, transmission, and processing power. Encoding the image information in quantum-mechanical systems instead of classical ones and replacing classical with quantum information processing may alleviate some of these challenges. By encoding and processing the image information in quantum-mechanical systems, we here demonstrate the framework of quantum image processing, where a pure quantum state encodes the image information: we encode the pixel values in the probability amplitudes and the pixel positions in the computational basis states. Our quantum image representation reduces the required number of qubits compared to existing implementations, and we present image processing algorithms that provide exponential speed-up over their classical counterparts. For the commonly used task of detecting the edge of an image, we propose and implement a quantum algorithm that completes the task with only one single-qubit operation, independent of the size of the image. This demonstrates the potential of quantum image processing for highly efficient image and video processing in the big data era.

Background: Although luteolin (Lut) is well recognized for its anti-inflammatory and antioxidant effects, its potential role in preventing vascular senescence remains underexplored in primary vascular aging. This study aimed to investigate the anti-vascular-aging effects of Lut in both cellular and murine aging models and to elucidate its conserved molecular mechanisms across species. Methods: Canine and feline vascular endothelial cells (cVECs and fVECs) were subjected to doxorubicin-induced senescence, while senescence-accelerated mice prone 8 (SAMP8) received an 8-week dietary supplementation with Lut. Senescence markers, inflammatory cytokines, antioxidant activities, vascular biomechanics, and histological changes were assessed. Transcriptomic and metabolomic analyses were combined to identify molecular pathways. Statistical significance was determined by one-way analysis of variance with Tukey’s or Games–Howell post hoc tests (p < 0.05). Results: Lut markedly reduced senescence-associated β-galactosidase activity, suppressed interleukin-6 and matrix metalloproteinase expression (p < 0.05), and enhanced superoxide dismutase activity and nicotinamide adenine dinucleotide levels (p < 0.05) in cVECs, fVECs, and SAMP8 sera. In aged mice, Lut alleviated arterial wall thickening and vascular inflammation, improved vascular biomechanics and systemic oxygenation (p < 0.05), and attenuated cardiac and hepatic inflammatory infiltration. Multi-omics analyses in cVECs revealed that Lut targets aldehyde dehydrogenase 1 to increase 9-cis retinoic acid, thereby activating the retinol X receptor–peroxisome proliferator-activated receptor (PPAR) network, which accelerates lipid clearance and oxidation. Consistent activation of this pathway was validated in murine vascular transcriptomes. Conclusions: These findings demonstrate that Lut delays vascular aging by activating the retinoic acid–PPAR axis and reprogramming lipid metabolism. This conserved mechanism was consistently observed in doxorubicin-induced cVEC senescence and the SAMP8 model, underscoring the robustness of Lut’s action across distinct contexts of vascular aging.

As a very fundamental principle in quantum physics, uncertainty principle has been studied intensively via various uncertainty inequalities. A natural and fundamental question is whether an equality exists for the uncertainty principle. Here we derive an entropic uncertainty equality relation for a bipartite system consisting of a quantum system and a coupled quantum memory, based on the information measure introduced by Brukner and Zeilinger (Phys. Rev. Lett. 83:3354, 1999). The equality indicates that the sum of measurement uncertainties over a complete set of mutually unbiased bases on a subsystem is equal to a total, fixed uncertainty determined by the initial bipartite state. For the special case where the system and the memory are the maximally entangled, all of the uncertainties related to each mutually unbiased base measurement are zero, which is substantially different from the uncertainty inequality relation. The results are meaningful for fundamental reasons and give rise to operational applications such as in quantum random number generation and quantum guessing games. Moreover, we experimentally verify the measurement uncertainty relation in the presence of quantum memory on a five-qubit spin system by directly measuring the corresponding quantum mechanical observables, rather than quantum state tomography in all the previous experiments of testing entropic uncertainty relations.

We investigate quantum state tomography（QST） for pure states and quantum process tomography（QPT） for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QST for all pure states. This idea is then extended to study QPT for unitary channels, where an adaptive unitary process tomography（AUPT） protocol of d2＋d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPT protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPT protocol when applied to Hadamard gate, T gate（/8 phase gate）, and controlled-NOT gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPT is also implemented for each gate. Our experimental results show that the AUPT protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPT without considerable loss of fidelity.

Quantum superposition is a fundamental principle of quantum mechanics, so it is not surprising that equal superposition states （ESS） serve as powerful resources for quantum information processing. In this work, we propose a quantum circuit that creates an arbitrary dimensional ESS. The circuit construction is efficient as the number of required elementary gates scales polynomially with the number of required qubits. For experimental realization of the method, we use techniques of nuclear magnetic resonance （NMR）. We have succeeded in preparing a 9-dimensional ESS on a 4-qubit NMR quantum register. The full tomography indicates that the fidelity of our prepared state with respect to the ideal 9-dimensional ESS is over 96%. We also prove the prepared state is pseudo-entangled by directly measuring an entanglement witness operator. Our result can be useful for the implementation of those quantum algorithms that require an ESS as an input state.

The influences of fish collagen peptide (FCP) and egg yolk lecithin (EYL) on the proliferation, fat accumulation and triglyceride content in feline adipocytes were investigated in this work, aiming at unveiling the mechanism of fat accumulation for cheek of feline animals. The lipogenic changes of adipocytes in the presence of FCP and EYL were determined by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results demonstrated that FCP of 10 mg/mL had the strongest cell activity, with a relative increment rate of 156 ± 0.23%, and the triglyceride content reached 215.9 ± 3.86 mmol/L. By comparison, it was observed that an EYL concentration of 5 mg/mL elicited the highest cell activity, exhibiting a relative increment rate of 152 ± 0.60%, and the level of triglyceride content was noted to reached 256.56 ± 25.68 mmol/L. After the feline adipocytes were treated with different concentrations of two active substances, fat formation and lipid droplets were found by oil red O staining. Liposome analyses confirmed that the formation of lipid compounds was regulated by FCP and EYL through pathways involved in lipid metabolism, notably including inositol phosphate insulin resistance, and phosphatidylinositol signaling pathways. This regulation was found to enhance cell vitality and facilitate fat accumulation. These findings provide a new strategy for the development of nutritional and healthy products or foods that promote feline cheek.

In this work, HengYan Wang and Jian Pan contributed equally to this work. The annotation for the contribution was omitted in the original publication of this paper [1]. It can be conformed in the submitted PDF version of the manuscript. Hence, the sentence “HengYan Wang and Jian Pan contributed equally to this work.” should be added.

Heat-bath algorithmic cooling (HBAC) has been proven to be a powerful and effective method for obtaining high polarization of the target system. Its cooling upper bound has been recently found using a specific algorithm, the partner pairing algorithm (PPA-HBAC). It has been shown that by including cross-relaxation, it is possible to surpass the cooling bounds. Herein, by combining cross-relaxation and decoherence-free subspace, we present a two-qubit reset sequence and then generate a new algorithmic cooling (AC) technique using irreversible polarization compression to further surpass the bound. The proposed two-qubit reset sequence can prepare one of the two qubits to four times the polarization of a single-qubit reset operation in PPA-HBAC for low polarization. When the qubit number is large, the cooling limit of the proposed AC is approximately five times as high as the PPA-HBAC. The results reveal that cross-relaxation and decoherence-free subspace are promising resources to create new AC for higher polarization.

Magnetic induction tomography (MIT) is a sensing protocol, exploring conductive objects via their response to radio-frequency magnetic fields. MIT is used in nondestructive testing ranging from geophysics to medical applications. Atomic magnetometers, employed as MIT sensors, allow for significant improvement of the MIT sensitivity and for exploring its quantum limits. Here we report entanglement-enhanced MIT with an atomic magnetometer used as the sensing element. We generate an entangled and spin squeezed state of atoms of the sensor by stroboscopic quantum non-demolition measurement. We then utilize this spin state to demonstrate the improvement of one-dimensional MIT sensitivity beyond the standard quantum limit.