Hasil untuk "quant-ph"

A. Vlasov

In recent work [quant-ph/0405174] by Schumacher and Werner was discussed an abstract algebraic approach to a model of reversible quantum cellular automata (CA) on a lattice. It was used special model of CA based on partitioning scheme and so there is a question about quantum CA derived from more general, standard model of classical CA. In present work is considered an approach to definition of a scheme with "history", valid for quantization both irreversible and reversible classical CA directly using local transition rules. It is used language of vectors in Hilbert spaces instead of C*-algebras, but results may be compared in some cases. Finally, the quantum lattice gases, quantum walk and "bots" are also discussed briefly.

Li Xiao, G. Long, Fuguo Deng et al.

In this work, we generalize the quantum-secret-sharing scheme of Hillery, Buzek, and Berthiaume [Phys. Rev. A 59, 1829 (1999)] into arbitrary multiparties. Explicit expressions for the shared secret bit is given. It is shown that in the Hillery-Buzek-Berthiaume quantum-secret-sharing scheme the secret information is shared in the parity of binary strings formed by the measured outcomes of the participants. In addition, we have increased the efficiency of the quantum-secret-sharing scheme by generalizing two techniques from quantum key distribution. The favored-measuring-basis quantum-secret-sharing scheme is developed from the Lo-Chau-Ardehali technique [H. K. Lo, H. F. Chau, and M. Ardehali, e-print quant-ph/0011056] where all the participants choose their measuring-basis asymmetrically, and the measuring-basis-encrypted quantum-secret-sharing scheme is developed from the Hwang-Koh-Han technique [W. Y. Hwang, I. G. Koh, and Y. D. Han, Phys. Lett. A 244, 489 (1998)] where all participants choose their measuring basis according to a control key. Both schemes are asymptotically 100% in efficiency, hence nearly all the Greenberger-Horne-Zeilinger states in a quantum-secret-sharing process are used to generate shared secret information.

Shiiv R S, Yuven Senthilkumar, V. Karthick

Ben Priestley, P. Wallden

The NP-hardness of the closest vector problem (CVP) is an important basis for quantum-secure cryptography, in much the same way that integer factorisation’s conjectured hardness is at the foundation of cryptosystems like RSA. Recent work with heuristic quantum algorithms (Yan et al 2022 arXiv:2212.12372 [quant-ph]) indicates the possibility to find close approximations to (constrained) CVP instances that could be incorporated within fast sieving approaches for factorisation. This work explores both the practicality and scalability of the proposed heuristic approach to explore the potential for a quantum advantage for approximate CVP, without regard for the subsequent factoring claims. We also extend the proposal to include an antecedent ‘pre-training’ scheme to find and fix a set of parameters that generalise well to increasingly large lattices, which both optimises the scalability of the algorithm, and permits direct numerical analyses. Our results further indicate a noteworthy quantum speed-up for lattice problems obeying a certain ‘prime’ structure, approaching fifth order advantage for quantum approximate optimisation algorithm of fixed depth p = 10 compared to classical brute-force, motivating renewed discussions about the necessary lattice dimensions for quantum-secure cryptosystems in the near-term.

P. Mannheim

When excited states decay the time evolution operator $U(t)=e^{-iHt}$ does not obey $U^{\dagger}(t)U(t)=I$. Nonetheless, probability conservation is not lost if one includes both excitation and decay, though it takes a different form. Specifically, if the eigenspectrum of a Hamiltonian is complete, then due to $CPT$ symmetry, a symmetry that holds for all physical systems, there must exist an operator $V$ that effects $VHV^{-1}=H^{\dagger}$, so that $V^{-1}U^{\dagger}(t)VU(t)=I$. In consequence, the time delay associated with decay must be accompanied by an equal and opposite time advance for excitation. Thus when a photon excites an atom the spontaneous emission of a photon from the excited state must occur without any decay time delay at all. An effect of this form together with an associated negative time delay appear to have recently been reported by Sinclair et. al., PRX Quantum \textbf{3}, 010314 (2022) and Angulo et. al., arXiv:2409.03680 [quant-ph].

G. Barbosa

The paper arXiv:2412.07300v1 [quant-ph] 10 Dec 2024, entitled"Structural Vulnerability in Y00 Protocols", by Kentaro Imafuku analyzes"Secure Communication Using Mesoscopic Coherent States", Phys. Rev. Lett., 90:227901, Jun 2003, by Geraldo A. Barbosa, Eric Corndorf, Prem Kumar, and Horace P. Yuen. Imafuku states that in his analyzes a structural vulnerability was revealed that enables the leakage of secret information from the measurement results in the Y00 protocol. Furthermore, it is also stated that an even simpler model, but based on the same original principles, can be more efficient than the original Y00 protocol. This reply shows that: 1) the alleged vulnerability is due to a misinterpretation of one result by Imafuku and 2) that the simple model proposed by him is more vulnerable than the original Y00.

J. A. Malla, Kharina J Fenton, Adinarayana Bellamkonda et al.

Abstract Ion channels are ubiquitous in Nature, performing complex and essential tasks in our bodies. Synthetic chemists have begun to understand how to form artificial channels, which hold great promise as components in artificial cells, and in synthetic biology more widely. Future generations of these systems will be critical in the treatment of channelopathies. Despite advances in synthetic ion transporters, the current generation cannot approach the selectivity and controllability of the biological ion channels they seek to emulate, and multimodal control over activity remains hard to achieve. Herein, we present a synthetic ion channel whose activity can be controlled by three orthogonal stimuli (light, pH, guest/ligand), based on a pillar[5]arene functionalized with photoswitchable ortho‐tetrafluoroazobenzene moieties. We demonstrate excellent control over ten photoswitches (E‐to‐Z 82%, Z‐to‐E quant.). We show that the most active Z‐isomer forms dimeric ion channels in membranes. Single molecule planar bilayer conductance studies show high and low conductance states dependent on irradiation wavelength. We demonstrate that this activity can be modulated over 170‐fold by controlling pH, irradiation, and guest addition. We use these three stimuli to design a pH switchable AND to OR logic gate system, creating a powerful addition to the canon of synthetic ion channels.

A. Kuhn, M. Hennrich, G. Rempe

Reply to the comment of H. J. Kimble [quant-ph/0210032] on the experiment realizing a "deterministic single-photon source for distributed quantum networking" by Kuhn, Hennrich, and Rempe [Phys. Rev. Lett. 89, 067901 (2002), quant-ph/0204147].

Mirko Arienzo, Dmitry Grinko, M. Kliesch et al.

Randomized benchmarking (RB) is the most commonly employed protocol for the characterization of unitary operations in quantum circuits due to its reasonable experimental requirements and robustness against state preparation and measurement (SPAM) errors. So far, the protocol has been limited to discrete or fermionic systems, whereas extensions to bosonic systems have been unclear for a long time due to challenges arising from the underlying bosonic Hilbert space. In this work, we close the gap for bosonic systems and develop an RB protocol to benchmark passive Gaussian transformations on any particle-number subspace, which we call . The protocol is built on top of the recently developed filtered RB framework [J. Helsen , PRX Quantum 3, 020357 (2022), M. Heinrich , Randomized benchmarking with random quantum circuits, arxiv:2212.06181 [quant-ph]] and is designed to isolate the multitude of exponential decays arising for passive bosonic transformations. We give explicit formulas and a Julia implementation for the necessary postprocessing of the experimental data. We also analyze the sampling complexity of passive bosonic RB by deriving analytical expressions for the variance. They show a mild scaling with the number of modes, suggesting that passive bosonic RB is experimentally feasible for a moderate number of modes. We focus on experimental settings involving Fock states and particle-number-resolving measurements, but also discuss Gaussian settings, deriving the first results for heterodyne measurements. Published by the American Physical Society 2025

Huw Price, Ken Wharton

We propose that quantum entanglement is a special sort of selection artefact, explicable as a combination of (i) collider bias and (ii) a boundary constraint on the collider variable. We show that the proposal is valid for a special class of (`W-shaped') Bell experiments involving delayed-choice entanglement swapping, and argue that it can be extended to the ordinary (`V-shaped') case. The proposal requires no direct causal influence outside lightcones, and may hence offer a way to reconcile Bell nonlocality and relativity. The main argument is a detailed version of an approach previously outlined in arXiv:2404.13928 [quant-ph].

Shu-Yuan 舒媛 Yang 杨, J. Hou 侯, Kan 衎 He 贺

Recently, a class of innovative notions on quantum network nonlocality (QNN), called full quantum network nonlocality (FQNN), have been proposed in Phys. Rev. Lett. 128 010403 (2022). As the generalization of full network nonlocality (FNN), l-level quantum network nonlocality (l-QNN) was defined in arxiv. 2306.15717 quant-ph (2024). FQNN is a NN that can be generated only from a network with all sources being non-classical. This is beyond the existing standard network nonlocality, which may be generated from a network with only a non-classical source. One of the challenging tasks is to establish corresponding Bell-like inequalities to demonstrate the FQNN or l-QNN. Up to now, the inequality criteria for FQNN and l-QNN have only been established for star and chain networks. In this paper, we devote ourselves to establishing Bell-like inequalities for networks with more complex structures. Note that star and chain networks are special kinds of tree-shaped networks. We first establish the Bell-like inequalities for verifying l-QNN in k-forked tree-shaped networks. Such results generalize the existing inequalities for star and chain networks. Furthermore, we find the Bell-like inequality criteria for l-QNN for general acyclic and cyclic networks. Finally, we discuss the demonstration of l-QNN in the well-known butterfly networks.

Huw Price

In previous work with Ken Wharton, it was proposed that Bell correlations are a special sort of selection artefact, explained by a combination of (i) collider bias and (ii) a boundary constraint on the collider variable. This requires no direct causal influence outside lightcones, and may hence offer a new way to reconcile Bell nonlocality and relativity. This piece outlines a new argument for the proposal. It explains how it is valid for a special class of ('W-shaped') Bell experiments involving delayed-choice entanglement swapping, and argues that it can be extended to the general ('V-shaped') case. A detailed version of the argument is now available in arXiv:2406.04571 [quant-ph].

A. Ramadhan, Ervina Wahyu Setyaningrum, Mega Yuniartik

Banyuwangi Regency has high potential for vannamei shrimp farming. Vannamei shrimp farming is susceptible to disease attack. Disease monitoring serves to determine the distribution of disease in vannamei shrimp ponds. The purpose of this study was to monitor disease in vannamei shrimp pond waters of Banyuwangi Regency. This research method uses descriptive method. Monitoring of water quality parameters insitu and exitu. Disease monitoring using Real-Time PCR Quant studio 5 to detect AHPND, WSSV, EHP, and IMNV. The analysis used was descriptive analysis. The results showed that the water quality in vannamei shrimp ponds in Banyuwangi Regency was an average temperature of 25.8℃, average salinity of 33.9 g.L-1 , average dissolved oxygen (DO) 7.15 mg.L-1 , average pH 8.15, average ammonia 0.257 mg.L-1 , average nitrite 0.04 mg.L-1 , average nitrate 4.9 mg.L-1 . As for the disease, there are three types, namely AHPND, EHP, and IMNV.

Labaran Ibrahim

The current study intends to evaluate the influence of seasonal changes on the water quality parameters of a coupled commercial aquaponics system. The determined water quality parameters for the comparative study were total ammonium-nitrogen (TAN), nitrate-nitrogen (NO3-N) and phosphate (PO43-), water temperature (WT), water pH, dissolved oxygen (DO), electrical conductivity (EC), and total dissolved solids (TDS). The WT and DO analysis were carried out using a portable dissolved oxygen meter (Model: PDO-520, Taiwan). A portable electrode pH meter (Model: PH-220, Taiwan) was utilized for the pH measurement. The TDS and EC readings were obtained using a multi-parameter water quality meter (PHT-27, China). The TAN, NO3-N, and PO43- determinations were done using their individual Merck Spectro-quant® test kits. The research results indicated a significant (p0.05) difference. The observed significant increase of NO3-N, PO43-, EC, and TDS in the summer and autumn periods could be associated to the increased fish feeding rate (which increases waste production) as well as relative increase in microbial waste conversion/mineralization. The investigated water quality makers were within the recommended amounts in the aquaponics system. Thus, in this study, seasonal differences have induced variation in the NO3-N, PO43-, WT, pH, EC, and TDS amounts. However, these differences do not affect the TAN and DO levels.

J. Rudolf-Scholik, D. Lilek, M. Maier et al.

Depending on the respective research question, LC-MS/MS based bottom-up proteomics poses challenges from the initial biological sample all the way to data evaluation. The focus of this study was to investigate the influence of sample preparation techniques and data analysis parameters on protein identification in Tribolium castaneum by applying free software proteomics platform Max Quant. Multidimensional protein extraction strategies in combination with electrophoretic or chromatographic off-line protein pre-fractionation were applied to enhance the spectrum of isolated proteins from T. castaneum and reduce the effect of co-elution and ion suppression effects during nano-LC-MS/MS measurements of peptides. For comprehensive data analysis, MaxQuant was used for protein identification and R for data evaluation. A wide range of parameters were evaluated to gain reproducible, reliable, and significant protein identifications. A simple phosphate buffer, pH 8, containing protease and phosphatase inhibitor cocktail and application of gentle extraction conditions were used as a first extraction step for T.castaneum proteins. Furthermore, a two-dimensional extraction procedure in combination with electrophoretic pre-fractionation of extracted proteins and subsequent in-gel digest resulted in almost 100% increase of identified proteins when compared to chromatographic fractionation as well as one-pot-analysis. The additionally identified proteins could be assigned to new molecular functions or cell compartments, emphasizing the positive effect of extended sample preparation in bottom-up proteomics. Besides the number of peptides during post-processing, MaxQuant's Match between Runs exhibited a crucial effect on the number of identified proteins. A maximum relative standard deviation of 2% must be considered for the data analysis. Our work with Tribolium castaneum larvae demonstrates that sometimes - depending on matrix and research question - more complex and time-consuming sample preparation can be advantageous for isolation and identification of additional proteins in bottom-up proteomics.

Ji Nny Song

Choi recently published a research paper on the subject of quantizing general time-dependent coupled oscillators (arXiv:2210.07551v1 [quant-ph] (2022)) using the invariant operator approach. In the present research, we provide a direct method for proving the correctness of such an invariant approach, together with relevant perspectives and criticisms. The difference of our method from Choi’s one in this context is that, while Choi managed the quantum system with the aid of the unitary transformation technique, we do not use such an auxiliary tool in our proof of accuracy. This demonstration may provide a definite mathematical testimony for the usefulness of adopting invariant operator approach in a straightforward way. Our proof is crucial in unfolding quantum information theory including opto-electromechanics via coupled devices which operate with electro-mechanical oscillations. We also discuss the consequences of Choi’s work and Zerimeche et al. ’s works (Mod. Phys. Lett. B 37, 2250222 (2023) and others) which share many concepts with each other, including the relation between them.

Agbokponto Engelbert, Daouda Mohamed M. Arêmou, Pokou Aurelle et al.

L’eau est un produit vital pour l’Homme, mais également une source de nombreuses maladies hydriques. Au Bénin, avec les changements de mode de vie, le conditionnement de l'eau s'est rapidement répandu, avec de nombreuses unités de production qui échappent au contrôle sanitaire des autorités mettant en danger la santé des consommateurs. Au total 70 unités de production dont 64 d’ensachage d’eau et 6 de mise en bouteilles d’eau dans 4 départements du sud du Bénin ont été inspectées et des échantillons de lot issu de production récente ont été prélevés pour des tests physicochimiques et microbiologiques. De l’analyse des résultats, il ressort des risques de contamination notés à l'inspection sanitaire notamment : l’absence de filtres à charbon obligatoires (64,1%) et de lampe UV (42,2%), la présence de fuite d’eau (14,1%) sur le circuit de production d’eau en sachet ainsi que le manque d’hygiène (34,4%). Les analyses de laboratoire quant à elles ont rapporté que le pH des échantillons d’eau variait entre 3,94 et 7,74 avec 48,57% de non-conformité (norme pH : 6,5-8,5). Les tests microbiologiques ont mis en évidence une contamination des eaux conditionnées par des germes banals (64,1% ; n=47), des présumés coliformes (7,1% ; n=5) et Escherichia coli (1,4% ; n=1). Cette mauvaise qualité microbiologique concerne aussi bien les échantillons d’eau conditionnée en sachet (n=44 sur 64) que les échantillons d’eau en bouteille (n=3 sur 6). Ces résultats montrent la nécessité de renforcer le suivi des installations de conditionnement d'eau afin d'assurer la sécurité sanitaire des consommateurs.

J. Roland, N. Cerf

The adiabatic theorem has been recently used to design quantum algorithms of a new kind, where the quantum computer evolves slowly enough so that it remains near its instantaneous ground state, which tends to the solution. We apply this time-dependent Hamiltonian approach to Grover’s problem, i.e., searching a marked item in an unstructured database. We find that by adjusting the evolution rate of the Hamiltonian so as to keep the evolution adiabatic on each infinitesimal time interval, the total running time is of order AN, where N is the number of items in the database. We thus recover the advantage of Grover’s standard algorithm as compared to a classical search, scaling as N. This is in contrast with the constant-rate adiabatic approach of Farhi et al. ~e-print quant-ph/0001106!, where the requirement of adiabaticity is expressed only globally, resulting in a time of order N.

Fu-Guo Deng, Gui Lu Long

Classical one-time-pad key can only be used once. We show in this Letter that with quantum mechanical information media classical one-time-pad key can be repeatedly used. We propose a specific realization using single photons. The reason why quantum mechanics can make the classical one-time-pad key repeatable is that quantum states can not be cloned and eavesdropping can be detected by the legitimate users. This represents a significant difference between classical cryptography and quantum cryptography and provides a new tool in designing quantum communication protocols and flexibility in practical applications. Note added: This work was submitted to PRL as LU9745 on 29 July 2004, and the decision was returned on 11 November 2004, which advised us to resubmit to some specialized journal, probably, PRA, after revision. We publish it here in memory of Prof. Fu-Guo Deng (1975.11.12-2019.1.18), from Beijing Normal University, who died on Jan 18, 2019 after two years heroic fight with pancreatic cancer. In this work, we designed a protocol to repeatedly use a classical one-time-pad key to transmit ciphertext using single photon states. The essential idea was proposed in November 1982, by Charles H. Bennett, Gilles Brassard, Seth Breidbart, which was rejected by Fifteenth Annual ACM Symposium on Theory of Computing, and remained unpublished until 2014, when they published the article, Quantum Cryptography II: How to re-use a one-time pad safely even if P=NP, Natural Computing (2014) 13:453-458, DOI 10.1007/s11047-014-9453-6. We worked out this idea independently. This work has not been published, and was in cooperated into quant-ph 0706.3791 (Kai Wen, Fu Guo Deng, Gui Lu Long, Secure Reusable Base-String in Quantum Key Distribution), and quant-ph 0711.1632 (Kai Wen, Fu-Guo Deng, Gui Lu Long, Reusable Vernam Cipher with Quantum Media).

Caroline Lantero