scholarly journals Engineering two-photon high-dimensional states through quantum interference

2016 ◽  
Vol 2 (2) ◽  
pp. e1501165 ◽  
Author(s):  
Yingwen Zhang ◽  
Filippus S. Roux ◽  
Thomas Konrad ◽  
Megan Agnew ◽  
Jonathan Leach ◽  
...  

Many protocols in quantum science, for example, linear optical quantum computing, require access to large-scale entangled quantum states. Such systems can be realized through many-particle qubits, but this approach often suffers from scalability problems. An alternative strategy is to consider a lesser number of particles that exist in high-dimensional states. The spatial modes of light are one such candidate that provides access to high-dimensional quantum states, and thus they increase the storage and processing potential of quantum information systems. We demonstrate the controlled engineering of two-photon high-dimensional states entangled in their orbital angular momentum through Hong-Ou-Mandel interference. We prepare a large range of high-dimensional entangled states and implement precise quantum state filtering. We characterize the full quantum state before and after the filter, and are thus able to determine that only the antisymmetric component of the initial state remains. This work paves the way for high-dimensional processing and communication of multiphoton quantum states, for example, in teleportation beyond qubits.

Author(s):  
Mevludin Licina

Dynamical high-dimensional quantum states can be tracked and manipulated in many cases. Using a new theoretical framework approach of manipulating quantum systems, we will show how one can manipulate and introduce parameters that allow tracking and descriptive insight in the dynamics of states. Using quantum topology and other novel mathematical representations, we will show how quantum states behave in critical points when the shift of probability distribution introduces changes.


2020 ◽  
Author(s):  
Saber Meamardoost ◽  
Mahasweta Bhattacharya ◽  
EunJung Hwang ◽  
Takaki Komiyama ◽  
Claudia Mewes ◽  
...  

AbstractThe inference of neuronal connectome from large-scale neuronal activity recordings, such as two-photon Calcium imaging, represents an active area of research in computational neuroscience. In this work, we developed FARCI (Fast and Robust Connectome Inference), a MATLAB package for neuronal connectome inference from high-dimensional two-photon Calcium fluorescence data. We employed partial correlations as a measure of the functional association strength between pairs of neurons to reconstruct a neuronal connectome. We demonstrated using gold standard datasets from the Neural Connectomics Challenge (NCC) that FARCI provides an accurate connectome and its performance is robust to network sizes, missing neurons, and noise levels. Moreover, FARCI is computationally efficient and highly scalable to large networks. In comparison to the best performing algorithm in the NCC, FARCI produces more accurate networks over different network sizes and subsampling, while providing over two orders of magnitude faster computational speed.


Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 118
Author(s):  
Andrea López-Incera ◽  
Pavel Sekatski ◽  
Wolfgang Dür

We study the effect of local decoherence on arbitrary quantum states. Adapting techniques developed in quantum metrology, we show that the action of generic local noise processes --though arbitrarily small-- always yields a state whose Quantum Fisher Information (QFI) with respect to local observables is linear in system size N, independent of the initial state. This implies that all macroscopic quantum states, which are characterized by a QFI that is quadratic in N, are fragile under decoherence, and cannot be maintained if the system is not perfectly isolated. We also provide analytical bounds on the effective system size, and show that the effective system size scales as the inverse of the noise parameter p for small p for all the noise channels considered, making it increasingly difficult to generate macroscopic or even mesoscopic quantum states. In turn, we also show that the preparation of a macroscopic quantum state, with respect to a conserved quantity, requires a device whose QFI is already at least as large as the one of the desired state. Given that the preparation device itself is classical and not a perfectly isolated macroscopic quantum state, the preparation device needs to be quadratically bigger than the macroscopic target state.


2013 ◽  
Vol 22 (12) ◽  
pp. 1341015 ◽  
Author(s):  
NISHANT AGARWAL ◽  
R. HOLMAN ◽  
ANDREW J. TOLLEY

We argue that a plausible operational definition for an initial state of the universe is the initial quantum state of the curvature perturbations generated during inflation. We provide a parametrization of this state and generalize the standard in–in formalism to incorporate the structures in this state into the computation of correlators of the perturbations. Measurements of these correlators using both the cosmic microwave background as well as large scale structure probe different structures in the initial state, as they give rise to bi- and tri-spectra peaked on different shapes of triangles and quadrilaterals in momentum space. In essence, the shapes implied by the correlators feed directly into information about the shape of the initial state and what physics could have preceded inflation to set this state up.


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiao-Min Hu ◽  
Wen-Bo Xing ◽  
Chao Zhang ◽  
Bi-Heng Liu ◽  
Matej Pivoluska ◽  
...  

Abstract Quantum entanglement is one of the most important resources in quantum information. In recent years, the research of quantum entanglement mainly focused on the increase in the number of entangled qubits or the high-dimensional entanglement of two particles. Compared with qubit states, multipartite high-dimensional entangled states have beneficial properties and are powerful for constructing quantum networks. However, there are few studies on multipartite high-dimensional quantum entanglement due to the difficulty of creating such states. In this paper, we experimentally prepared a multipartite high-dimensional state $$\left|{\Psi }_{442}\right\rangle =\frac{1}{2}(\left|000\right\rangle +\left|110\right\rangle +\left|221\right\rangle +\left|331\right\rangle )$$ Ψ 442 = 1 2 ( 000 + 110 + 221 + 331 ) by using the path mode of photons. We obtain the fidelity F = 0.854 ± 0.007 of the quantum state, which proves a real multipartite high-dimensional entangled state. Finally, we use this quantum state to demonstrate a layered quantum network in principle. Our work highlights another route toward complex quantum networks.


2021 ◽  
Author(s):  
Hui Zhang ◽  
Lingxiao Wan ◽  
Tobias Haug ◽  
Wai-Keong Mok ◽  
Hong Cai ◽  
...  

Abstract Quantum teleportation transfers unknown quantum states from one node in a quantum network to another. It is one of the crucial architectures in quantum information processing. The teleportation of high-dimensional quantum states remains challenging due to the difficulties in executing high-dimensional Bell state measurement. Here, we propose a Quantum Autoencoder-Facilitated Teleportation (QAFT) protocol for high-dimensional quantum teleportation, and report the first demonstration of QAFT on qutrits using an integrated photonic platform for future scalability. The key strategy is to reduce the dimension of the input states by erasing redundant information and reconstruct its initial state after chip-to-chip teleportation. Machine learning is applied in training the autoencoder to facilitate the teleportation of any state from a particular high-dimensional subspace and achieve the reconstruction of the unknown state (by the decoder) with high fidelities (~ 0.971). Experimentally, we teleport unknown qutrits by generating, transferring and manipulating photons, and training quantum autoencoders on a silicon chip. A teleportation fidelity of ~ 0.894 is demonstrated. Our scheme opens pathway towards quantum internet and cryptography to transfer unmeasured states in a quantum computer. It also lays the groundwork for machine learning technologies in quantum networks and quantum computations.


1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.


2009 ◽  
Vol 35 (7) ◽  
pp. 859-866
Author(s):  
Ming LIU ◽  
Xiao-Long WANG ◽  
Yuan-Chao LIU

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 566.1-566
Author(s):  
S. Afilal ◽  
H. Rkain ◽  
B. Berchane ◽  
J. Moulay Berkchi ◽  
S. Fellous ◽  
...  

Background:Methotrexate is a gold standard for treatment of RA. In our context, RA patients prefer to be injected by paramedics rather than self-injecting. This can be explained by patients’ bad perceptions of self-injection or lack of information. Appropriate self-injection education can therefore be an important element in overcoming these obstacles and improving disease self-management.Objectives:Compare the RA patients’ perceptions on methotrexate self-injection before and after a patient education session.Methods:Prospective pilot study that included 27 consecutive patients (81.5% female, mean age 44.4 years, illiteracy rate 40.7%) with RA (median duration of progression of 4 years, mean delay in referral for specialist of 6 months, median duration of methotrexate use of 1 year). The patients benefited from an individual patient education session to learn how to self-inject with methotrexate subcutaneously. The patient education session was supervised by a nurse and a rheumatologist with a control a week later. Perceptions of the reluctance to self-inject and the difficulties encountered by patients were assessed before the patient education session, after the 1st and 2nd self-injection of methotrexate using a 10 mm visual analog scale. Patients also reported their level of satisfaction (10 mm VAS) after the 1st and 2nd self-injection.Results:The mean duration of patient education session is 13 min.Table I compares the evolution of the degrees of reluctance to self-injection, the difficulties encountered, and the satisfaction experienced by the patients.Table 1.Evolution of RA patients’ perceptions on the methotrexate self-injection. (N = 27)BeforeAfter the 1stself-injectionAfter the 2end self-injectionpVAS reluctance (0-10mm)6,5 ± 3,62,2 ± 2,91,0 ± 2,3<0,0001VAS difficulty (0-10mm)7,5 ± 2,62,5 ± 2,71,0 ± 1,9<0,0001VAS satisfaction (0-10mm)-8,9 ± 1,89,5 ± 1,50,002Conclusion:This study suggests the effectiveness of a methotrexate self-injection patient education session in RA patients. It also highlights the value of patient education in rheumatologic care. A large-scale study is necessary to better interpret and complete these preliminary results from this pilot study.Disclosure of Interests:None declared


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