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error correction circuit

U Vool, S Shankar, S O Mundhada, N Ofek, A Narla, K Sliwa, E Zalys-Geller, Y Liu, L Frunzio, R J Schoelkopf, S M Girvin, M H Devoret
Quantum jumps of a qubit are usually observed between its energy eigenstates, also known as its longitudinal pseudospin component. Is it possible, instead, to observe quantum jumps between the transverse superpositions of these eigenstates? We answer positively by presenting the first continuous quantum nondemolition measurement of the transverse component of an individual qubit. In a circuit QED system irradiated by two pump tones, we engineer an effective Hamiltonian whose eigenstates are the transverse qubit states, and a dispersive measurement of the corresponding operator...
September 23, 2016: Physical Review Letters
Ying Li
Fault-tolerant quantum computing in systems composed of both Majorana fermions and topologically unprotected quantum systems, e.g., superconducting circuits or quantum dots, is studied in this Letter. Errors caused by topologically unprotected quantum systems need to be corrected with error-correction schemes, for instance, the surface code. We find that the error-correction performance of such a hybrid topological quantum computer is not superior to a normal quantum computer unless the topological charge of Majorana fermions is insusceptible to noise...
September 16, 2016: Physical Review Letters
Yuan Yang, Nannan Quan, Jingjing Bu, Xueping Li, Ningmei Yu
BACKGROUND: High order modulation and demodulation technology can solve the frequency requirement between the wireless energy transmission and data communication. In order to achieve reliable wireless data communication based on high order modulation technology for visual prosthesis, this work proposed a Reed-Solomon (RS) error correcting code (ECC) circuit on the basis of differential amplitude and phase shift keying (DAPSK) soft demodulation. Firstly, recognizing the weakness of the traditional DAPSK soft demodulation algorithm based on division that is complex for hardware implementation, an improved phase soft demodulation algorithm for visual prosthesis to reduce the hardware complexity is put forward...
September 26, 2016: Biomedical Engineering Online
Gregory L Hanna, Yanni Liu, Yona E Isaacs, Angela M Ayoub, Jose J Torres, Nolan B O'Hara, William J Gehring
OBJECTIVE: The pathophysiology of obsessive-compulsive disorder (OCD) involves increased activity in corticostriatal circuits connecting the anterior cingulate cortex with other brain regions. The error-related negativity (ERN) is a negative deflection in the event-related potential after an incorrect response that is believed to reflect anterior cingulate cortex activity. This study examined the relation of the ERN to OCD symptom dimensions and other childhood symptom dimensions. METHOD: The ERN, correct response negativity, and accuracy were measured during a flanker task to assess performance monitoring in 80 youth with a lifetime diagnosis of OCD and 80 matched healthy comparison participants ranging from 8 to 18 years old...
October 2016: Journal of the American Academy of Child and Adolescent Psychiatry
Chung-Chuan Lo, Xiao-Jing Wang
Automatic responses enable us to react quickly and effortlessly, but they often need to be inhibited so that an alternative, voluntary action can take place. To investigate the brain mechanism of controlled behavior, we investigated a biologically-based network model of spiking neurons for inhibitory control. In contrast to a simple race between pro- versus anti-response, our model incorporates a sensorimotor remapping module, and an action-selection module endowed with a "Stop" process through tonic inhibition...
August 2016: PLoS Computational Biology
Therese Riedemann, Hans Reiner Polder, Bernd Sutor
We present a technique which combines two methods in order to measure the series resistance (R S) during whole-cell patch-clamp recordings from excitable and non-excitable cells. R S is determined in the amplifier's current-clamp mode by means of an active bridge circuit. The correct neutralization of the electrode capacitance and the adjustment of the bridge circuit is achieved by the so-called phase-sensitive method: Short sine wave currents with frequencies between 3 and 7 kHz are injected into the cells...
October 2016: Pflügers Archiv: European Journal of Physiology
He Lu, Zhen Zhang, Luo-Kan Chen, Zheng-Da Li, Chang Liu, Li Li, Nai-Le Liu, Xiongfeng Ma, Yu-Ao Chen, Jian-Wei Pan
Secret sharing of a quantum state, or quantum secret sharing, in which a dealer wants to share a certain amount of quantum information with a few players, has wide applications in quantum information. The critical criterion in a threshold secret sharing scheme is confidentiality: with less than the designated number of players, no information can be recovered. Furthermore, in a quantum scenario, one additional critical criterion exists: the capability of sharing entangled and unknown quantum information. Here, by employing a six-photon entangled state, we demonstrate a quantum threshold scheme, where the shared quantum secrecy can be efficiently reconstructed with a state fidelity as high as 93%...
July 15, 2016: Physical Review Letters
Nissim Ofek, Andrei Petrenko, Reinier Heeres, Philip Reinhold, Zaki Leghtas, Brian Vlastakis, Yehan Liu, Luigi Frunzio, S M Girvin, L Jiang, Mazyar Mirrahimi, M H Devoret, R J Schoelkopf
Quantum error correction (QEC) can overcome the errors experienced by qubits and is therefore an essential component of a future quantum computer. To implement QEC, a qubit is redundantly encoded in a higher-dimensional space using quantum states with carefully tailored symmetry properties. Projective measurements of these parity-type observables provide error syndrome information, with which errors can be corrected via simple operations. The 'break-even' point of QEC--at which the lifetime of a qubit exceeds the lifetime of the constituents of the system--has so far remained out of reach...
August 25, 2016: Nature
P Balasubramanian
N-modular redundancy (NMR) is a generic fault tolerance scheme that is widely used in safety-critical circuit/system designs to guarantee the correct operation with enhanced reliability. In passive NMR, at least a majority (N + 1)/2 out of N function modules is expected to operate correctly at any time, where N is odd. Apart from a conventional realization of the NMR system, it would be useful to provide a concurrent indication of the system's health so that an appropriate remedial action may be initiated depending upon an application's safety criticality...
2016: SpringerPlus
R Barends, A Shabani, L Lamata, J Kelly, A Mezzacapo, U Las Heras, R Babbush, A G Fowler, B Campbell, Yu Chen, Z Chen, B Chiaro, A Dunsworth, E Jeffrey, E Lucero, A Megrant, J Y Mutus, M Neeley, C Neill, P J J O'Malley, C Quintana, P Roushan, D Sank, A Vainsencher, J Wenner, T C White, E Solano, H Neven, John M Martinis
Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise...
June 9, 2016: Nature
Seong-Min Choi
Cerebellar circuitry is important to controlling and modifying motor activity. It conducts the coordination and correction of errors in muscle contractions during active movements. Therefore, cerebrovascular lesions of the cerebellum or its pathways can cause diverse movement disorders, such as action tremor, Holmes' tremor, palatal tremor, asterixis, and dystonia. The pathophysiology of abnormal movements after stroke remains poorly understood. However, due to the current advances in functional neuroimaging, it has recently been described as changes in functional brain networks...
May 2016: Journal of Movement Disorders
Evgeni V Nikolaev, Eduardo D Sontag
Synthetic constructs in biotechnology, biocomputing, and modern gene therapy interventions are often based on plasmids or transfected circuits which implement some form of "on-off" switch. For example, the expression of a protein used for therapeutic purposes might be triggered by the recognition of a specific combination of inducers (e.g., antigens), and memory of this event should be maintained across a cell population until a specific stimulus commands a coordinated shut-off. The robustness of such a design is hampered by molecular ("intrinsic") or environmental ("extrinsic") noise, which may lead to spontaneous changes of state in a subset of the population and is reflected in the bimodality of protein expression, as measured for example using flow cytometry...
April 2016: PLoS Computational Biology
Eliot Kapit
Superconducting qubits are among the most promising platforms for building a quantum computer. However, individual qubit coherence times are not far past the scalability threshold for quantum error correction, meaning that millions of physical devices would be required to construct a useful quantum computer. Consequently, further increases in coherence time are very desirable. In this Letter, we blueprint a simple circuit consisting of two transmon qubits and two additional lossy qubits or resonators, which is passively protected against all single-qubit quantum error channels through a combination of continuous driving and engineered dissipation...
April 15, 2016: Physical Review Letters
Bo Yang, Xingjun Wang, Yunpeng Deng, Di Hu
This paper presents technology for the suppression of the mechanical coupling errors for an improved decoupled dual-mass micro-gyroscope (DDMG). The improved micro-gyroscope structure decreases the moment arm of the drive decoupled torque, which benefits the suppression of the non-ideal decoupled error. Quadrature correction electrodes are added to eliminate the residual quadrature error. The structure principle and the quadrature error suppression means of the DDMG are described in detail. ANSYS software is used to simulate the micro-gyroscope structure to verify the mechanical coupling error suppression effect...
2016: Sensors
Brigitta Kakuszi, László Tombor, Szilvia Papp, István Bitter, Pál Czobor
Aberrations in early-developing bottom-up processes, such as stimulus-driven response preparation, are thought to play a critical role in the onset of ADHD, and in its persistence over time. Electrophysiology offers a unique tool to gain insight into response preparation, since response preparation has been associated with distinctive ERP changes, including negative potential-shifts which occur predominantly over frontal brain areas. We examined response-preceding negative potential shifts (RPNS) as a probe of response-preparation in adult ADHD patients by obtaining high-density event-related potentials from 33 ADHD and 29 matched healthy subjects during a Go/Nogo task using a 128-channel BioSemi recording-system...
March 30, 2016: Psychiatry Research
Xiaodan Liu, Keita Watanabe, Shingo Kakeda, Reiji Yoshimura, Osamu Abe, Satoru Ide, Kenji Hayashi, Asuka Katsuki, Wakako Umene-Nakano, Rieko Watanabe, Issei Ueda, Jun Nakamura, Yukunori Korogi
BACKGROUND: Higher daytime cortisol levels because of a hyperactive hypothalamic-pituitary-adrenal axis have been reported in patients with major depressive disorder (MDD). The elevated glucocorticoids inhibit the proliferation of the oligodendrocytes that are responsible for myelinating the axons of white matter fibre tracts. AIMS: To evaluate the relationship between white matter integrity and serum cortisol levels during a first depressive episode in drug-naive patients with MDD (MDD group) using a tract-based spatial statistics (TBSS) method...
June 2016: British Journal of Psychiatry: the Journal of Mental Science
Huiliang Cao, Hongsheng Li, Zhiwei Kou, Yunbo Shi, Jun Tang, Zongmin Ma, Chong Shen, Jun Liu
This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses' quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced...
2016: Sensors
Mehedi Hasan, Rabiaa Guemri, Ramón Maldonado-Basilio, Frédéric Lucarz, Jean-Louis de Bougrenet de la Tocnaye, Trevor Hall
A novel photonic circuit design for implementing frequency 8-tupling and 24-tupling was presented [Opt. Lett.39, 6950 (2014)10.1364/OL.39.006950OPLEDP0146-9592], and although its key message remains unaltered, there were typographical errors in the equations that are corrected in this erratum.
December 15, 2015: Optics Letters
Marta Pallotto, Paul V Watkins, Boma Fubara, Joshua H Singer, Kevin L Briggman
Dense connectomic mapping of neuronal circuits is limited by the time and effort required to analyze 3D electron microscopy (EM) datasets. Algorithms designed to automate image segmentation suffer from substantial error rates and require significant manual error correction. Any improvement in segmentation error rates would therefore directly reduce the time required to analyze 3D EM data. We explored preserving extracellular space (ECS) during chemical tissue fixation to improve the ability to segment neurites and to identify synaptic contacts...
December 9, 2015: ELife
Lisa M Giocomo
Ubiquitous throughout the animal kingdom, path-integration based navigation allows an animal to take a circuitous route out from a home base and using only self-motion cues, calculate a direct vector back. Despite variation in an animal's running speed and direction, medial entorhinal grid cells fire in repeating place-specific locations, pointing to the medial entorhinal circuit as a potential neural substrate for path-integration based spatial navigation. Supporting this idea, grid cells appear to provide an environment-independent metric representation of the animal's location in space and preserve their periodic firing structure even in complete darkness...
November 13, 2015: Journal of Physiology
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