Dual Quantum Research Articles

Innovative Integration of Dual Quantum Cascade Lasers on Silicon Photonics Platform.

For the first time, we demonstrate the hybrid integration of dual distributed feedback (DFB) quantum cascade lasers (QCLs) on a silicon photonics platform using an innovative 3D self-aligned flip-chip assembly process. The QCL waveguide geometry was predesigned with alignment fiducials, enabling a sub-micron accuracy during assembly. Laser oscillation was observed at the designed wavelength of 7.2 μm, with a threshold current of 170 mA at room temperature under pulsed mode operation. The optical output power after an on-chip beam combiner reached sub-milliwatt levels under stable continuous wave operation at 15 °C. The specific packaging design miniaturized the entire light source by a factor of 100 compared with traditional free-space dual lasers module. Divergence values of 2.88 mrad along the horizontal axis and 1.84 mrad along the vertical axis were measured after packaging. Promisingly, adhering to i-line lithography and reducing the reliance on high-end flip-chip tools significantly lowers the cost per chip. This approach opens new avenues for QCL integration on silicon photonic chips, with significant implications for portable mid-infrared spectroscopy devices.

Quantum dual-path interferometry scheme for axion dark matter searches

Exploring the mysterious dark matter is a key quest in modern physics. Currently, detecting axions, a hypothetical particle proposed as a primary component of dark matter, remains a significant challenge due to their weakly interacting nature. Here we show at quantum level that in a cavity permeated by a magnetic field, the single axion-photon conversion rate is enhanced by the cavity quality factor and is quantitatively larger than the classical result by π/2. The axion cavity can be considered a quantum device emitting single photons with temporal separations. This differs from the classical picture and reveals a possibility for the axion cavity experiment to handle the signal sensitivity at the quantum level, e.g., a dual path quantum interferometry with cross-power and second-order correlation measurements. This scheme would greatly reduce the signal scanning time and improve the sensitivity of the axion-photon coupling, potentially leading to the direct observation of axions.

Rapid detection of OTA and ZEN with dual quantum dots fluorescence immunochromatographic test strip

Rapid detection of OTA and ZEN with dual quantum dots fluorescence immunochromatographic test strip

Unraveling carrier distribution in far-UVC LEDs by temperature-dependent electroluminescence measurements

The hole transport and the carrier distribution in AlGaN-based far-ultraviolett (UVC) light emitting diodes (LEDs) emitting around 233 nm was investigated. Temperature-dependent electroluminescence measurements on dual wavelength AlGaN multiple quantum well (MQW) LEDs show a strong shift in the spectral power distribution from 250 to 233 nm with decreasing temperature. Comparing experimental data with simulation shows that the hole mobility and the electron to hole mobility ratios have a significant influence on the carrier injection efficiency (CIE) and that the change in the spectral power distribution is originating from a change in the hole distribution in the MQWs. Poor hole injection and charge carrier confinement in the AlGaN MQW active region was identified as one of the main reasons for the low CIE in far-UVC LEDs.

Fluorescent and colorimetric dual-readout platform for tuberculosis point-of-care detection based on dual signal amplification strategy and quantum dot nanoprobe

Rapid and accurate diagnosis of tuberculosis (TB) is of great significance to control the spread of this devastating infectious disease. In this work, a sensitive and low-cost point-of-care testing (POCT) detection platform for TB was developed based on recombinase polymerase amplification (RPA)-catalytic hairpin assembly (CHA)-assisted dual signal amplification strategy. This platform could achieve homogeneous fluorescent and visual diagnosis of TB by using CdTe quantum dots (QDs) signal reporter. In the presence of target DNA (IS1081 gene fragment), RPA amplicons blocked by short oligonucleotide strands could trigger CHA signal amplification, leading to the Ag+ releasing from C–Ag+-C structure and the fluorescence quenching of CdTe QDs by the released Ag+. Furthermore, the detection performance of CdTe QDs modified by 3-mercaptopropionic acid (MPA) or thiomalic acid (TMA) (MPA-capped QDs and TMA-capped QDs) was systematically compared. Experimental results demonstrated that TMA-capped QDs exhibited better detection sensitivity due to their stronger interaction with Ag+. The limits of detection (LODs) of fluorescence and visual analysis were as low as 0.13 amol L−1 and 0.33 amol L−1. This method was successfully applied to the clinical sputum samples from 36 TB patients and 20 healthy individuals, and its quantitative results were highly consistent with those obtained by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). The proposed approach has the advantages of high sensitivity and specificity, simple operation and low cost, and is expected to be applied in clinical TB screening and diagnosis.

Switchable Quantized Signal between Longitudinal Conductance and Hall Conductance in Dual Quantum Spin Hall Insulator TaIrTe4.

Topological insulating states in 2-dimensional (2D) materials are ideal systems to study different types of quantized response signals due to their in gap metallic states. Very recently, the quantum spin Hall effect was discovered in monolayer TaIrTe4 via the observation of quantized longitudinal conductance that rarely exists in other 2D topological insulators. The nontrivial Z 2 topological charges can exist at both charge neutrality point and the van Hove singularity point with correlation-effect-induced bandgap. On the basis of this model 2D material, we studied the switch of quantized signals between longitudinal conductance and transversal Hall conductance via tuning external magnetic field. In Z 2 topological phase of monolayer TaIrTe4, the zero Chern number can be understood as 1 - 1 = 0 from the double band inversion from spin-up and spin-down channels. After applying a magnetic field perpendicular to the plane, the Zeeman split changes the band order for one branch of the band inversion from spin-up and spin-down channels, along with a sign charge of the Berry phase. Then, the net Chern number of 1 - 1 = 0 is tuned to 1 + 1 = 2 or -1 - 1 = -2 depending on the orientation of the magnetic field. The quantized signal not only provides another effective method for the verification of topological state in monolayer TaIrTe4 but also offers a strategy for the utilization of the new quantum topological states based on switchable quantized responses.

Entanglement structures from modified IR geometry

We investigate a new proposal connecting the geometry at various radial scales in asymptotic AdS spacetime with entanglement structure at corresponding real-space length scales of the boundary theory. With this proposal, the bulk IR geometry encodes the long-scale entanglement structure of the dual quantum system. We consider two distinct types of IR geometries, namely the spherical case and the hyperbolic case, which are intimately related to the physics of differential entropy and brane-world holography separately. We explore the corresponding change in the dual long-scale entanglement structures, utilizing the tools of the Ryu-Takayanagi formula, conditional mutual information, and partial entanglement entropy. The results indicate that modifying the IR geometry leads to a redistribution of entanglement at scales longer than a critical length determined by the location of the IR region, with the two modified IR geometries corresponding to two opposite ways of redistribution. Furthermore, we establish the maximum amount of entanglement that can be modified, which is proportional to the area of the IR region.

Spacetime-localized response in quantum critical spin systems: Insights from holography

According to the AdS/CFT correspondence, certain quantum many-body systems in d-dimensions are equivalent to gravitational theories in (d+1)-dimensional asymptotically anti–de Sitter (AdS) spacetimes. When a massless particle is sent from the AdS boundary to the bulk curved spacetime, it reaches another point of the boundary after a time lag. In the dual quantum system, it should appear as if quasiparticles have been transferred between two separated points. We theoretically demonstrate that this phenomenon, which we call “spacetime-localized response”, is actually observed in the dynamics of the one-dimensional transverse-field Ising model near the quantum critical point. This result suggests that, if we can realize a holographic spin system in a laboratory, the experimental probing of the emergent extra dimension is possible by applying a designed stimulus to a quantum many-body system, which is holographically equivalent to sending a massless particle through the higher-dimensional curved bulk geometry. We also discuss possible experimental realizations using Rydberg atoms in an optical tweezers array. Published by the American Physical Society 2024

Enhanced photoelectric performance of dual cations quantum dots carbon-based perovskite solar cells with stacked structure

Enhanced photoelectric performance of dual cations quantum dots carbon-based perovskite solar cells with stacked structure

Higher categorical symmetries and gauging in two-dimensional spin systems

We present a framework to systematically investigate higher categorical symmetries in two-dimensional spin systems. Though exotic, such generalised symmetries have been shown to naturally arise as dual symmetries upon gauging invertible symmetries. Our framework relies on an approach to dualities whereby dual quantum lattice models only differ in a choice of module 2-category over some input fusion 2-category. Given an arbitrary two-dimensional spin system with an ordinary symmetry, we explain how to perform the (twisted) gauging of any of its sub-symmetries. We then demonstrate that the resulting model has a symmetry structure encoded into the Morita dual of the input fusion 2-category with respect to the corresponding module 2-category. We exemplify this approach by specialising to certain finite group generalisations of the transverse-field Ising model, for which we explicitly define lattice symmetry operators organised into fusion 2-categories of higher representations of higher groups.

Precise Layer-by-Layer Assembly of Dual Quantum Dots Artificial Photosystems Enabling Solar Water Oxidation.

Quantum dots (QDs) colloidal nanocrystals are attracting enduring interest by scientific communities for solar energy conversion due to generic physicochemical merits including substantial light absorption coefficient, quantum confinement effect, enriched catalytically active sites, and tunable electronic structure. However, photo-induced charge carriers of QDs suffer from ultra-short charge lifespan and poor stability, rendering controllable vectorial charge modulation and customizing robust and stable QDs artificial photosystems challenging. Herein, tailor-made oppositely charged transition metal chalcogenides quantum dots (TMCs QDs) and MXene quantum dots (MQDs) are judiciously harnessed as the building blocks for electrostatic layer-by-layer assembly buildup on the metal oxides (MOs) framework. In these exquisitely designed LbL assembles MOs/(TMCs QDs/MQDs)n heterostructured photoanodes, TMCs QDs layer acts as light-harvesting antennas, and MQDs layer serves as electron-capturing mediator to relay cascade electrons from TMCs QDs to the MOs substrate, thereby yielding the spatially ordered tandem charge transport chain and contributing to the significantly boosted charge separation over TMCs QDs and solar water oxidation efficiency of MOs/(TMCs QDs/MQDs)n photoanodes. The relationship between interface configuration and charge transfer characteristics is unambiguously unlocked, by which photoelectrochemical mechanism is elucidated. This work would provide inspiring ideas for precisely mediating interfacial charge transfer pathways over QDs toward solar energy conversion.

Dual quantum spin Hall insulator by density-tuned correlations in TaIrTe4.

The convergence of topology and correlations represents a highly coveted realm in the pursuit of new quantum states of matter1. Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order2-8, not possible in quantum Hall and Chern insulator systems. Here we report a new dual QSH insulator within the intrinsic monolayer crystal of TaIrTe4, arising from the interplay of its single-particle topology and density-tuned electron correlations. At charge neutrality, monolayer TaIrTe4 demonstrates the QSH insulator, manifesting enhanced nonlocal transport and quantized helical edge conductance. After introducing electrons from charge neutrality, TaIrTe4 shows metallic behaviour in onlya small range of charge densities but quickly goes into a new insulating state, entirely unexpected on the basis of the single-particle band structure of TaIrTe4. This insulating state could arise from a strong electronic instability near the van Hove singularities, probably leading to a charge density wave (CDW). Remarkably, within this correlated insulating gap, we observe a resurgence of the QSH state. The observation of helical edge conduction in a CDW gap could bridge spin physics and charge orders. The discovery of a dual QSH insulator introduces a new method for creating topological flat minibands through CDW superlattices, which offer a promising platform for exploring time-reversal-symmetric fractional phases and electromagnetism2-4,9,10.

Single-Cell Liquid Biopsy of Lung Cancer: Ultra-Simplified Efficient Enrichment of Circulating Tumor Cells and Hand-Held Fluorometer Portable Testing.

Herein, we propose a paper-based laboratory via enzyme-free nucleic acid amplification and nanomaterial-assisted cation exchange reactions (CERs) assisted single-cell-level analysis (PLACS). This method allowed for the rapid detection of mucin 1 and trace circulating tumor cells (CTCs) in the peripheral blood of lung cancer patients. Initially, an independently developed method requiring one centrifuge, two reagents (lymphocyte separation solution and erythrocyte lysate), and a three-step, 45 min sample pretreatment was employed. The core of the detection approach consisted of two competitive selective identifications: copper sulfide nanoparticles (CuS NPs) to C-Ag+-C and Ag+, and dual quantum dots (QDs) to Cu2+ and CuS NPs. To facilitate multimodal point-of-care testing (POCT), we integrated solution visualization, test strip length reading, and a self-developed hand-held fluorometer readout. These methods were detectable down to ag/mL of mucin 1 concentration and the single-cell level. Forty-seven clinical samples were assayed by fluorometer, yielding 94% (30/32) sensitivity and 100% (15/15) specificity with an area under the curve (AUC) of 0.945. Nine and 15 samples were retested by a test strip and hand-held fluorometer, respectively, with an AUC of 0.95. All test results were consistent with the clinical imaging and the folate receptor (FR)-PCR kit findings, supporting its potential in early diagnosis and postoperative monitoring.

A ratiometric fluorescence probe based on dual quantum dots for methyl parathion detection in agricultural products

Methyl parathion (MP) is an organic phosphorus pesticide widely used for pest control of various crops, however, the residual MP can enter the human body and damage the nervous system. Therefore, it is necessary to effectively monitor MP residues. Based on dual-fluorescent quantum dots, this study establishes a ratio fluorescence sensing platform for MP detection, wherein the probe is β-cyclodextrin (β-CD) modified molybdenum disulfide quantum dots (MoS2 QDs) called β-CD-MoS2 QDs. Under alkaline conditions, MP is hydrolyzed into p-nitrophenol (p-NP) and enters the hydrophobic cavity of β-CD, quenching the blue fluorescence of MoS2 QDs whose quenching degree of fluorescence intensity (I400) correlates with the concentration of MP, while the fluorescence intensity (I540) of gQDs remains unchanged and is selected as reference signal. The quantitative detection of MP is conducted by calculating the ratio of fluorescence intensities (I540/I400). The probe detected MP in the range of 0.05–25 ppm with a detection limit of 0.032 ppm which is proved to meet the requirements for biological sample detection according to the methodological validation results. The probe has been successfully applied for the detection of MP in apples and vegetables, confirming its applicability for MP detection in crops.

Cosmological constant as quantum error correction from generalized gauge invariance in double field theory

The holographic principle and its realization as the anti-de Sitter/conformal field theory (AdS/CFT) correspondence leads to the existence of the so-called precursor operators. These are boundary operators that carry nonlocal information regarding events occurring deep inside the bulk and which cannot be causally connected to the boundary. Such nonlocal operators can distinguish nonvacuum-like excitations within the bulk that cannot be observed by any local gauge invariant operators in the boundary. The boundary precursors are expected to become increasingly nonlocal the further the bulk process is from the boundary. Such phenomena are expected to be related to the extended nature of the strings. Standard gauge invariance in the boundary theory equates to quantum error correction which furthermore establishes localization of bulk information. I show that when double field theory quantum error correction prescriptions are considered in the bulk, gauge invariance in the boundary manifests residual effects associated to stringy winding modes. Also, an effect of double field theory quantum error correction is the appearance of positive cosmological constant. The emergence of space–time from the entanglement structure of a dual quantum field theory appears in this context to generalize for de Sitter space–times as well.

Lieb-Schultz-Mattis anomalies and web of dualities induced by gauging in quantum spin chains

Lieb-Schultz-Mattis (LSM) theorems impose non-perturbative constraints on the zero-temperature phase diagrams of quantum lattice Hamiltonians (always assumed to be local in this paper). LSM theorems have recently been interpreted as the lattice counterparts to mixed ’t Hooft anomalies in quantum field theories that arise from a combination of crystalline and global internal symmetry groups. Accordingly, LSM theorems have been reinterpreted as LSM anomalies. In this work, we provide a systematic diagnostic for LSM anomalies in one spatial dimension. We show that gauging subgroups of the global internal symmetry group of a quantum lattice model obeying an LSM anomaly delivers a dual quantum lattice Hamiltonian such that its internal and crystalline symmetries mix non-trivially through a group extension. This mixing of crystalline and internal symmetries after gauging is a direct consequence of the LSM anomaly, i.e., it can be used as a diagnostic of an LSM anomaly. We exemplify this procedure for a quantum spin-1/2 chain obeying an LSM anomaly resulting from combining a global internal \mathbb{Z}^{\,}_{2}×\mathbb{Z}^{\,}_{2}ℤ2×ℤ2 symmetry with translation or reflection symmetry. We establish a triality of models by gauging a \mathbb{Z}^{\,}_{2}\subset\mathbb{Z}^{\,}_{2}×\mathbb{Z}^{\,}_{2}ℤ2⊂ℤ2×ℤ2 symmetry in two ways, one of which amounts to performing a Kramers-Wannier duality, while the other implements a Jordan-Wigner duality. We discuss the mapping of the phase diagram of the quantum spin-1/2 XYZXYZ chains under such a triality. We show that the deconfined quantum critical transitions between Neel and dimer orders are mapped to either topological or conventional Landau-Ginzburg transitions. Finally, we extend our results to \mathbb{Z}^{\,}_{n}ℤn clock models with \mathbb{Z}^{\,}_{n}×\mathbb{Z}^{\,}_{n}ℤn×ℤn global internal symmetry, and provide a reinterpretation of the dual internal symmetries in terms of \mathbb{Z}^{\,}_{n}ℤn charge and dipole symmetries.

Parallel detection of mixed pesticides based on dual quantum dot/porous silicon optical biosensors

Parallel detection of mixed pesticides based on dual quantum dot/porous silicon optical biosensors

Selectively activated suppressed quantum networks in self-assembled single-atom Ag catalyst-based room-temperature sensors for health monitoring

Dual mode quantum pathways in 2-step self-assembly mediated hybrid sensor system ensures multifunctional utility in ex situ and in situ breathe alcohol monitoring.

Dual emission quaternary alloyed quantum dots for white light-emitting diodes with high color-rendering index

We report the synthesis of manganese doped Ag–Zn–In–S(AZIS)/ZnS QDs for the facile fabrication of white light-emitting diodes (WLEDs). By controlling the ratio of Mn/(Zn + In), dual emission Mn:AZIS/ZnS QDs with different relative proportion of host emission and Mn2+-related emission were prepared. With proper doping, the emission of Mn: AZIS/ZnS QDs covers most of the visible spectrum. Based on the as prepared Mn:AZIS/ZnS QDs, a warm WLED device exhibited a highest color rendering index (CRI) of 92.5 companied by a correlated color temperature (CCT) of 3162 K. With the increasing of Mn2+ concentration, the corresponding WLED devices shown warmer CCT values and lower luminous efficiencies (LEs). The color-conversion efficiency of the QDs decreasing with the increasing of Mn2+ concentration may be responsible partly for the variation of device LEs. With further deep investigation on the mechanism of color-conversion between the exciting light and QDs, and the energy transfer from the host material to the manganese dopant, WLEDs based on the dual emission Mn:AZIS/ZnS QDs with better device performances are excepted to find diverse application in lighting fields.

Cosmological quantum states of de Sitter-Schwarzschild are static patch partition functions

We solve the Wheeler-DeWitt equation in the ‘cosmological interior’ (the past causal diamond of future infinity) of four dimensional dS-Schwarzschild spacetimes. Within minisuperspace there is a basis of solutions labelled by a constant c, conjugate to the mass of the black hole. We propose that these solutions are in correspondence with partition functions of a dual quantum mechanical theory where c plays the role of time. The quantum mechanical theory lives on worldtubes in the ‘static patch’ of dS-Schwarzschild, and the partition function is obtained by evolving the corresponding Wheeler-DeWitt wavefunction through the cosmological horizon, where a metric component gtt changes sign. We establish that the dual theory admits a symmetry algebra given by a central extension of the Poincaré algebra e\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathfrak{e} $$\\end{document}(1, 1) and that the entropy of the dS black hole is encoded as an averaging of the dual partition function over the background gtt.