Dynamically Error-Corrected Gates for Universal Quantum Computation

Scalable quantum computation in realistic devices requires that precise control can be implemented efficiently in the presence of decoherence and operational errors. We propose a general constructive procedure for designing robust unitary gates on an open quantum system without encoding or measurement overhead. Our results allow for a low-level error correction strategy solely based on Hamiltonian engineering using realistic bounded-strength controls and may substantially reduce implementation requirements for fault-tolerant quantum computing architectures.Comment: 5 pages, 3 figure

MARKOV DIFFUSIONS IN COMOVING COORDINATES AND STOCHASTIC QUANTIZATION OF THE FREE RELATIVISTIC SPINLESS PARTICLE

We revisit the classical approach of comoving coordinates in relativistic hydrodynamics and we give a constructive proof for their global existence under suitable conditions which is proper for stochastic quantization. We show that it is possible to assign stochastic kinematics for the free relativistic spinless particle as a Markov diffusion globally defined on ${\sf M}^4$. Then introducing dynamics by means of a stochastic variational principle with Einstein's action, we are lead to positive-energy solutions of Klein-Gordon equation. The procedure exhibits relativistic covariance properties.Comment: 31 pages + 1 figure available upon request; Plain REVTe

Factors Affecting the Accuracy of Eyewitness Identification

In lieu of an abstract, below is the article\u27s first paragraph. We\u27ve all experienced, at one time or another, our own memories failing us at times, and this may have been due to a number of factors. Perhaps the issue at hand was not important to us at the time, and therefore we devoted little attention to it. But imagine being in the scenario Wells (1993) suggests in the following passage: Suppose that you were an eyewitness to a crime. Perhaps it was a theft, a burglary, a mugging, a drive-by shooting, or a robbery. You might or might not have known that a crime was being committed at the time; perhaps you saw someone exit a building that exploded a short time later. Perhaps you were the victim or perhaps you were a bystander. Regardless of the circumstances, there exists some memory trace, however strong or weak, that could have important consequences for the course of justice. Because you have seen the culprit, the police ask you to give a description. Later, perhaps only hours or perhaps months later, you are called to the police station to attempt an identification of the culprit. You are then shown a lineup or a photo spread and asked to indicate whether the person you saw on that fateful occasion is one of the people standing or pictured before you on this day. (p. 553) Many factors influence the accuracy of recall and identity of a face, some of which we have little to no control over. Given the right conditions, these factors will influence how one\u27s memory recalls the specific features that make one face distinct from another

Mengidentifikasi Gesture Siswa dalam Menyelesaikan Soal Matematika Siswa Kelas VII di SMP N 2 Ampek Angkek

Learning activities are basically communication activities because in the learning process, teachers and students are involved in the process of delivering messages, using media, and receiving messages. Gestures are spontaneous movements of the hands or body which generally occur during face-to-face conversations. The movement is a gesture to convey a message in the form of an impression in a way that words cannot. Gestures are divided into four main categories, namely (1) iconic gestures, (2) metaphoric gestures, (3) deitic gestures and (4) beat gestures. The purpose of this study was to find out what gestures were made by class VII students of SMP N 2 Ampek Angkek during the learning process. The type of research conducted is descriptive qualitative. Sampling of this study used the Proposive Sampling technique. Data collection was carried out by observation, interviews, and video. It was concluded that students used iconic gestures 30 times, deictic gestures 25 times, and metaphoric gestures 5 times when solving math problems in comparative material. The benefits of this gesture are carried out by students who explain material in solving mathematical problems, among others, to focus attention on the intended object, describe the object being thought of, focus attention on the object being discussed, and concretize the idea being thought of. The use of gestures can also make it easier for students or listeners to understand and easily understand the material being studied or the information conveyed

Experimental Implementation of a Concatenated Quantum Error-Correcting Code

Concatenated coding provides a general strategy to achieve the desired level of noise protection in quantum information storage and transmission. We report the implementation of a concatenated quantum error-correcting code able to correct against phase errors with a strong correlated component. The experiment was performed using liquid-state nuclear magnetic resonance techniques on a four spin subsystem of labeled crotonic acid. Our results show that concatenation between active and passive quantum error-correcting codes offers a practical tool to handle realistic noise contributed by both independent and correlated errors.Comment: 4 pages, 2 encapsulated eps figures. REVTeX4 styl

Advances in decoherence control

I address the current status of dynamical decoupling techniques in terms of required control resources and feasibility. Based on recent advances in both improving the theoretical design and assessing the control performance for specific noise models, I argue that significant progress may still be possible on the road of implementing decoupling under realistic constraints.Comment: 14 pages, 3 encapsulated eps figures. To appear in Journal of Modern Optics, Special Proceedings Volume of the XXXIV Winter Colloquium on the Physics of Quantum Electronics, Snowbird, Jan 200

Quantum Information Encoding, Protection, and Correction from Trace-Norm Isometries

We introduce the notion of trace-norm isometric encoding and explore its implications for passive and active methods to protect quantum information against errors. Beside providing an operational foundations to the "subsystems principle" [E. Knill, Phys. Rev. A 74, 042301 (2006)] for faithfully realizing quantum information in physical systems, our approach allows additional explicit connections between noiseless, protectable, and correctable quantum codes to be identified. Robustness properties of isometric encodings against imperfect initialization and/or deviations from the intended error models are also analyzed.Comment: 10 pages, 1 figur

Penerapan Model Discovery Learning (Dl) Menggunakan Peta Konsep Untuk Meningkatkan Hasil Belajar Biologi Siswa Kelas XI IPA SMA Taruna Pekanbaru T.p 2015/2016

This research aimed to improve learning outcomes biology class XI Science SMA Taruna Pekanbaru through the implementation model of Discovery Learning (DL) using the Concept Map, the research was conducted in SMA Taruna Pekanbaru in April-May 2016. The parameters measured were the result study of cognitive, affective and psychomotor. The methods of this research was classroom action research. It had been done in two cylce. There were planning step, acting step, observation step and reflection step for each cycle. The research instrument used was learning devices and data collection instruments. The data obtained were analyzed descriptively. The results of this study indicate the cognitive aspects of daily tests first cycle that 80.97 (Enough) increased in the second cycle into 84.67 (enough). Students who complete the first cycle of 27 students (89.91%) and the second cycle is 27 students (89.91%). While the average aspect of attitude in the first cycle that 67.40 (Less) and increased in the second cycle into 87.19 (Good). Furthermore, the average in the first cycle that psychomotor aspects 78.90 (Enough) and increased in the second cycle into 91.81 (good). Based on these data we can conclude that the application of the model of Discovery Learning (DL) using Concept Maps can improve learning outcomes biology class XI Science Senior High School Taruna Pekanbaru