Interfacing external quantum devices to a universal quantum computer

We present a scheme to use external quantum devices using the universal quantum computer previously constructed. We thereby show how the universal quantum computer can utilize networked quantum information resources to carry out local computations. Such information may come from specialized quantum devices or even from remote universal quantum computers. We show how to accomplish this by devising universal quantum computer programs that implement well known oracle based quantum algorithms, namely the Deutsch, Deutsch-Jozsa, and the Grover algorithms using external black-box quantum oracle devices. In the process, we demonstrate a method to map existing quantum algorithms onto the universal quantum computer.     

Creating self-illuminating quantum dot conjugates

Semiconductor quantum dots are inorganic fluorescent nanocrystals that, because of their unique optical properties compared with those of organic fluorophores, have become popular as fluorescent imaging probes. Although external light excitation is typically required for imaging with quantum dots, a new type of quantum dot conjugate has been reported that can luminesce with no need for external excitation. These self-illuminating quantum dot conjugates can be prepared by coupling of commercially available carboxylate-presenting quantum dots to the light-emitting protein Renilla luciferase. When the conjugates are exposed to the luciferase's substrate coelenterazine, the energy released by substrate catabolism is transferred to the quantum dots through bioluminescence resonance energy transfer, leading to quantum dot light emission. This protocol describes step-by-step procedures for the preparation and characterization of these self-illuminating quantum dot conjugates. The preparation process is relatively simple and can be done in less than 2 hours. The availability of self-illuminating quantum dot conjugates will provide many new possibilities for in vivo imaging and detection, such as monitoring of in vivo cell trafficking, multiplex bioluminescence imaging and new quantum dot-based biosensors.     

Targeted nuclear delivery using peptide-coated quantum dots

Core/shell quantum dots (CdSe/Zns) conjugated with various nuclear localization signaling (NLS) peptides, which could facilitate the transportation of quantum dots across the plasma membrane into the nucleus, have been utilized to investigate the uptake mechanism of targeted delivery. Because of their brightness and photostability, it was possible to trace the trajectories of individual quantum dots in living cells using both confocal and total internal reflection microscopes. We found that, when the quantum dots were added to a cell culture, the peptide-coated quantum dots entered the cell nucleus while the uncoated quantum dots remained in the cytoplasm. At 8 nM, most of the peptide coated quantum dots were found in the cytoplasm due to aggregation. However, at a lower concentration (0.08 nM), approximately 25% of the NLS peptide-coated quantum dots entered the cell nucleus. We also found that some quantum dots without NLS coating could also enter the nucleus, suggesting that the size of the quantum dots may play an important role in such a process.     

Quorum sensing: a quantum perspective

Quorum sensing is the efficient mode of communication in the bacterial world. After a lot of advancements in the classical theory of quorum sensing few basic questions of quorum sensing still remain unanswered. The sufficient progresses in quantum biology demands to explain these questions from the quantum perspective as non trivial quantum effects already have manifested in various biological processes like photosynthesis, magneto-reception etc. Therefore, it’s the time to review the bacterial communications from the quantum view point. In this article we carefully accumulate the latest results and arguments to strengthen quantum biology through the addition of quorum sensing mechanism in the light of quantum mechanics.     

含镉量子点的毒性研究进展

含镉量子点是典型的量子点,近年来受到广泛研究。含镉量子点的潜在毒性是其在生物成像及生物医药方面应用和发展的关键制约因素,因此,对其毒性作用的研究具有重要意义。目前对含镉量子点的体外毒性研究主要集中在人肝癌细胞(HepG2)、神经分泌细胞(PC12)等细胞实验及斑马鱼胚胎体外培养实验。体内毒性研究包括小鼠等动物实验。这些研究证实,量子点对HepG2等细胞系和小鼠、贻贝等动物均具细胞毒性。研究者们普遍认为,量子点是通过释放其组成中的重金属,诱导生物体产生活性氧自由基,进而引发细胞凋亡或自噬,但对量子点的具体毒性作用机制并不完全清楚。该文对含镉量子点的体内和体外毒性研究工作进展进行了综述,包括含镉量子点对肝肾细胞、神经细胞、血液细胞及免疫细胞等体外毒性研究工作,对陆生及水生动物等的体内毒性研究工作,旨在更好、更全面地评估含镉量子点的毒性,为今后对量子点的毒性作用机制研究提供方向,促进含镉量子点在生物医学方面的发展和应用。     

Imaging of cell surface antigens on tumor lymph-node sections using fluorescence quantum dots

In this work we explored the potential of quantum dots for fluorescent detection of lymphoid surface antigens. To optimize detection with quantum dots, we upgraded a fluorescent microscope that allowed us obtaining multiple images from different quantum dots on a single section. Specimens stained with quantum dots remained stable over two weeks and practically did not bleach under the mercury lamp during scores of minutes. Double staining of frozen sections with direct conjugates of quantum dots with primary mouse monoclonal antibodies demonstrated direct conjugate high specificity and sensitivity. High stability of quantum dots’ fluorescence allows their use in diagnostics to analyze antigen coexpression on lymphoid tissue sections. “Spillover” of fluorescent signals from quantum dots into adjacent fluorescent channels maximally separated by 40 nm did not exceed 8%, which renders spectral compensation unnecessary.     

Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and entanglement, to solve certain problems exponentially faster than with the best known algorithms on a classical computer. Gate-defined lateral quantum dots on GaAs/AlGaAs are one of many avenues explored for the implementation of a qubit. When properly fabricated, such a device is able to trap a small number of electrons in a certain region of space. The spin states of these electrons can then be used to implement the logical 0 and 1 of the quantum bit. Given the nanometer scale of these quantum dots, cleanroom facilities offering specialized equipment- such as scanning electron microscopes and e-beam evaporators- are required for their fabrication. Great care must be taken throughout the fabrication process to maintain cleanliness of the sample surface and to avoid damaging the fragile gates of the structure. This paper presents the detailed fabrication protocol of gate-defined lateral quantum dots from the wafer to a working device. Characterization methods and representative results are also briefly discussed. Although this paper concentrates on double quantum dots, the fabrication process remains the same for single or triple dots or even arrays of quantum dots. Moreover, the protocol can be adapted to fabricate lateral quantum dots on other substrates, such as Si/SiGe.     

Collapsing a Perfect Superposition to a Chosen Quantum State without Measurement

Given a perfect superposition of states on a quantum system of qubits. We propose a fast quantum algorithm for collapsing the perfect superposition to a chosen quantum state without applying any measurements. The basic idea is to use a phase destruction mechanism. Two operators are used, the first operator applies a phase shift and a temporary entanglement to mark in the superposition, and the second operator applies selective phase shifts on the states in the superposition according to their Hamming distance with . The generated state can be used as an excellent input state for testing quantum memories and linear optics quantum computers. We make no assumptions about the used operators and applied quantum gates, but our result implies that for this purpose the number of qubits in the quantum register offers no advantage, in principle, over the obvious measurement-based feedback protocol.     

量子点在生物学中的研究进展

量子点作为一种新型的荧光标记物近年来已在生物学中获得广泛应用。本文总结了量子点的主要光学特性,其中包括荧光激发和发射光谱特性、量子产额、光漂白特性和荧光寿命等。重点综述了量子点在细胞标记、活体和组织成像、组合标记和光动力学治疗等生物学中的应用及其最新研究进展。同时讨论了量子点在应用中可能存在的细胞毒性等主要问题,最后对量子点在生物学中的应用前景作了展望。     

Speculation on Quantum Mechanics and the Operation of Life Giving Catalysts

The origin of life necessitated the formation of catalytic functionalities in order to realize a number of those capable of supporting reactions that led to the proliferation of biologically accessible molecules and the formation of a proto-metabolic network. Here, the discussion of the significance of quantum behavior on biological systems is extended from recent hypotheses exploring brain function and DNA mutation to include origins of life considerations in light of the concept of quantum decoherence and the transition from the quantum to the classical. Current understandings of quantum systems indicate that in the context of catalysis, substrate-catalyst interaction may be considered as a quantum measurement problem. Exploration of catalytic functionality necessary for life’s emergence may have been accommodated by quantum searches within metal sulfide compartments, where catalyst and substrate wave function interaction may allow for quantum based searches of catalytic phase space. Considering the degree of entanglement experienced by catalytic and non catalytic outcomes of superimposed states, quantum contributions are postulated to have played an important role in the operation of efficient catalysts that would provide for the kinetic basis for the emergence of life.     

Examination of the stability of hydrophobic (CdSe)ZnS quantum dots in the digestive tract of rats.

Semiconductor quantum dots show promise as alternatives to organic dyes for biological labelling because of their bright and stable photoluminescence. The typical quantum dots is CdSe because colloidal synthesis for nanocrystals of this semiconductor is well established. CdSe is usually passivated with zinc sulfide. While the cytotoxicity of bulk CdSe is well documented, questions about (CdSe)ZnS potential toxicity and behaviour in vivo remain unanswered. The distribution and stability of (CdSe)ZnS quantum dots in Wistar line rats' digestive tract were investigated. Hydrophobic quantum dots were mixed with fat or sonificated in water and administered orally. The distribution and stability of quantum dots moving through the digestive system of rats was followed by fluorescence spectroscopy. In both ways prepared quantum dots were degraded in the digestive tract of animals. Quantum dots mixed with fat were more stable and degraded more slowly than quantum dots sonificated in water. The data obtained suggest possible toxicity of (CdSe)ZnS quantum dots due to the liberation of Cd(2+).     

Dielectric permittivity of quantum plasma. Part II

The transverse and longitudinal dielectric permittivities of isotropic quantum plasma are calculated in the quantum plasma models based on the Dirac and Pauli equations. The dispersion relations for transverse-longitudinal waves in quantum particle beams are derived. Relativistic longitudinal and transverse waves in cold isotropic quantum plasma in models based on the Klein-Gordon and Dirac equations, as well as spin waves in the model based on the Pauli equation, are considered. Conditions for wave-particle resonance interactions in relativistic quantum plasma are analyzed.     

Nanoantenna-Enhanced Radiative and Anisotropic Decay Rates in Monolayer-Quantum Dots

Plasmonics - Nanoantenna-enhanced ultrafast emission from colloidal quantum dots as quantum emitters is required for fast quantum communications. On-chip integration of such devices requires a...     

Imaging of surface cell antigens on the tumor sections of lymph nodes using fluorescence quantum dots

The usefulness of quantum dots for the immunofluorescent detection of surface antigens on the lymphoid cells has been studied. To optimize quantum dots detection we have upgraded fluorescent microscope that allows obtaining multiple images from different quantum dots from one section. Specimens stained with quantum dots remained stable over two weeks and practically did not bleach under mercury lamp illumination during tens of minutes. Direct conjugates of primary mouse monoclonal antibodies with quantum dots demonstrated high specificity and sufficient sensitivity in the case of double staining on the frozen sections. Because of the high stability of quantum dots' fluorescence, this method allows to analyze antigen coexpression on the lymphoid tissue sections for diagnostic purposes. The spillover of fluorescent signals from quantum dots into adjacent fluorescent channels, with maxima differing by 40 nm, did not exceed 8%, which makes the spectral compensation is practically unnecessary.     

Forming and maintaining a heat engine for quantum biology

Chemical reactions upholding biological functions and structures are the process of measurement taking place among the participating chemical reactants. Chemical reactions occurring in thermal environments are either endothermic or exothermic. In particular, exothermic reactions that can live with temperature gradients of exogenous origin could potentially be competent enough to synthesize a robust quantum as a heat engine. Molecular organizations leading to the origin of the phenomenon of life might have been associated with the emergence of a quantum coherence embodied in a robust heat engine feeding on quantum decoherence. Evolutionary maintenance of a robust quantum heat engine, once appeared, can further be empowered by the build-up of temperature gradients of endogenous origin. Biology enriches the repertoire of quantum mechanics so as to include a robust heat engine as a legitimate member of a quantum in addition to the already established member of a quantum including an atom, molecule, and macromolecule.     

Conduction pathways in microtubules, biological quantum computation, and consciousness.

Technological computation is entering the quantum realm, focusing attention on biomolecular information processing systems such as proteins, as presaged by the work of Michael Conrad. Protein conformational dynamics and pharmacological evidence suggest that protein conformational states-fundamental information units ('bits') in biological systems-are governed by quantum events, and are thus perhaps akin to quantum bits ('qubits') as utilized in quantum computation. 'Real time' dynamic activities within cells are regulated by the cell cytoskeleton, particularly microtubules (MTs) which are cylindrical lattice polymers of the protein tubulin. Recent evidence shows signaling, communication and conductivity in MTs, and theoretical models have predicted both classical and quantum information processing in MTs. In this paper we show conduction pathways for electron mobility and possible quantum tunneling and superconductivity among aromatic amino acids in tubulins. The pathways within tubulin match helical patterns in the microtubule lattice structure, which lend themselves to topological quantum effects resistant to decoherence. The Penrose-Hameroff 'Orch OR' model of consciousness is reviewed as an example of the possible utility of quantum computation in MTs.     

The quantum Zeno effect immunizes the avian compass against the deleterious effects of exchange and dipolar interactions

Magnetic-sensitive radical-ion-pair reactions are understood to underlie the biochemical magnetic compass used by avian species for navigation. Recent experiments have provided growing evidence for the radical-ion-pair magnetoreception mechanism, while recent theoretical advances have unravelled the quantum nature of radical-ion-pair reactions, which were shown to manifest a host of quantum-information-science concepts and effects, like quantum measurement, quantum jumps and the quantum Zeno effect. We here show that the quantum Zeno effect provides for the robustness of the avian compass mechanism, and immunizes its magnetic and angular sensitivity against the deleterious and molecule-specific exchange and dipolar interactions.     

Parameter Estimation of Fractional-Order Chaotic Systems by Using Quantum Parallel Particle Swarm Optimization Algorithm

Parameter estimation for fractional-order chaotic systems is an important issue in fractional-order chaotic control and synchronization and could be essentially formulated as a multidimensional optimization problem. A novel algorithm called quantum parallel particle swarm optimization (QPPSO) is proposed to solve the parameter estimation for fractional-order chaotic systems. The parallel characteristic of quantum computing is used in QPPSO. This characteristic increases the calculation of each generation exponentially. The behavior of particles in quantum space is restrained by the quantum evolution equation, which consists of the current rotation angle, individual optimal quantum rotation angle, and global optimal quantum rotation angle. Numerical simulation based on several typical fractional-order systems and comparisons with some typical existing algorithms show the effectiveness and efficiency of the proposed algorithm.     

Quantum computing: a new paradigm for ecology

A global technology arms race is underway to build evermore powerful and precise quantum computers. Quantum computers have the potential to tackle certain quantitative problems quicker than classical computers. The current focus of quantum computing is on pushing the boundaries of fundamental quantum information and commercial applications in industrial sectors, financial services, and other profit-led sectors, particularly where improvements in optimisation and sampling can improve increased economic return. We believe that ecologists could exploit the computational power of quantum computers because the statistical approaches commonly used in ecology already have proven pathways on quantum computers. Moreover, quantum computing could ultimately leapfrog our understanding of complex ecological systems, if the hardware, opportunity, and creativity of quantitative ecologists all align.