Remote preparation of quantum states

Remote state preparation is the variant of quantum state teleportation in which the sender knows the quantum state to be communicated. The original paper introducing teleportation established minimal requirements for classical communication and entanglement but the corresponding limits for remote state preparation have remained unknown until now: previous work has shown, however, that it not only requires less classical communication but also gives rise to a trade-off between these two resources in the appropriate setting. We discuss this problem from first principles, including the various choices one may follow in the definitions of the actual resources. Our main result is a general method of remote state preparation for arbitrary states of many qubits, at a cost of 1 bit of classical communication and 1 bit of entanglement per qubit sent. In this "universal" formulation, these ebit and cbit requirements are shown to be simultaneously optimal by exhibiting a dichotomy. Our protocol then yields the exact trade-off curve for arbitrary ensembles of pure states and pure entangled states (including the case of incomplete knowledge of the ensemble probabilities), based on the recently established quantum-classical trade-off for quantum data compression. The paper includes an extensive discussion of our results, including the impact of the choice of model on the resources, the topic of obliviousness, and an application to private quantum channels and quantum data hiding.Comment: 21 pages plus 2 figures (eps), revtex4. v2 corrects some errors and adds obliviousness discussion. v3 has section VI C deleted and various minor oversights correcte

A Randomized Waitlist-controlled Trial of Voice Over Internet Protocol-delivered Behavior Therapy for Chronic Tic Disorders

Videoconferencing is efficacious, acceptable and equivalent to face to face for a range of psychotherapies, including a Comprehensive Behavioral Interventions for Tics (CBIT), but limited due to lack of portability, and restricted accessibility. An alternative is Voice over Internet Protocol (VoIP) transmission, allowing home delivery of treatment. The present study examined the preliminary efficacy, feasibility, and acceptability of CBIT-VoIP. Twenty youth (8-17) with CTDs participated in a randomized, waitlist-controlled trial of CBIT. Assessments were conducted via VoIP and internet surveys. Significantly greater reductions in total clinician-rated and parent-reported tic severity were found in the CBIT relative to the waitlist-control group, with 33.3% of those in CBIT considered treatment responders. Treatment satisfaction and the therapeutic alliance were high. Higher parent satisfaction with videoconferencing was associated with higher decreases in clinician-rated tic severity. Positive relationships were found between child computer usage at baseline and satisfaction with videoconferencing at post-assessment. VoIP was generally feasible, with some challenges due to audio and visual disruptions

Comparing Fixed-Amount and Progressive-Amount Schedules of Reinforcement for Tic Suppression

Chronic tic disorders (CTDs) involve motor and/or vocal tics that cause substantial distress and impairment. Existing behavioral interventions for CTDs have comparable efficacy to pharmacological treatments but still leave many individuals with significant tic symptoms and impairment. One approach to improving existing treatments involves conducting pre-clinical laboratory research to evaluate procedures that may be attractive candidates for applied treatment research. Reinforcing tic suppression via differential reinforcement of other behavior (DRO) procedures produces decreases in tic frequency of ~80% in youth with CTDs; however, a more robust reduction may be needed to affect durable clinical change. The present study compared the effects of a novel, progressive-amount DRO schedule for tic suppression and a standard DRO schedule representative of that used in previous research. Five youth with CTDs were exposed to periods of baseline, traditional/fixed-amount DRO (DRO-F), and progressive-amount DRO (DRO-P). Both DRO schedules decreased tic rate and inter-tic interval duration. However, no systematic differences between the two DRO schedules were observed on measures of tic occurrence, premonitory urge strength, or subjective stress. The DRO-F schedule was generally preferred to the DRO-P schedule. The DRO-P procedure did not yield more desirable effects than the DRO-F schedule. Basic and applied implications of this study and future directions for CTD treatment development research are discussed

A Course chapter on Quantum Computing for Master Students in Engineering

Quantum computing is a rapidly evolving field encompassing various disciplines such as physics, mathematics, computer engineering, and computer science. Teaching quantum computing in a concise and effective manner can be challenging, especially within the time constraints of a single course or a short period, even for graduate students. This challenge is particularly relevant in two-year MSc programs that include a thesis, which is a typical structure in higher education systems in the USA and Europe. In this paper, the author proposes an approach to teaching quantum computing and shares their experience of conducting a course chapter on the subject within a two-week time frame. The experience reported in this paper is integrated into the "Technologies of Computing Systems" (TCS) course, with a total workload of 6 ECTS (in the context of the European Credit Transfer and Accumulation System, one ECTS corresponds to 28 hours of work), conducted in one quarter, over seven weeks. The structure of the course chapter is discussed, involving a series of lectures that were accompanied by lab classes and a lab project, allowing students to receive guidance while also engaging in hands-on learning and independent study. The paper provides an overview of the quantum computing topics covered, and their integration in the TSC course, and gives details about how these topics are studied in the different types of classes. It also discusses the evaluation procedure and presents the results obtained. It can be concluded that the inclusion of the quantum computing component not only significantly increased student interest in the course but also effectively bridged the gap between classical and quantum computing for engineering students within a short period of two weeks.Comment: 10 pages, 7 figure

Weak Decoupling Duality and Quantum Identification

If a quantum system is subject to noise, it is possible to perform quantum error correction reversing the action of the noise if and only if no information about the system's quantum state leaks to the environment. In this article, we develop an analogous duality in the case that the environment approximately forgets the identity of the quantum state, a weaker condition satisfied by epsilon-randomizing maps and approximate unitary designs. Specifically, we show that the environment approximately forgets quantum states if and only if the original channel approximately preserves pairwise fidelities of pure inputs, an observation we call weak decoupling duality. Using this tool, we then go on to study the task of using the output of a channel to simulate restricted classes of measurements on a space of input states. The case of simulating measurements that test whether the input state is an arbitrary pure state is known as equality testing or quantum identification. An immediate consequence of weak decoupling duality is that the ability to perform quantum identification cannot be cloned. We furthermore establish that the optimal amortized rate at which quantum states can be identified through a noisy quantum channel is equal to the entanglement-assisted classical capacity of the channel, despite the fact that the task is quantum, not classical, and entanglement-assistance is not allowed. In particular, this rate is strictly positive for every non-constant quantum channel, including classical channels.Comment: 14 pages; v2 has some remarks added and inaccuracies corrected; v3 has new title, improved presentation and additional references; v4 is the final, accepted version (to appear in IEEE IT), title changed once more and numerous improvements made - the main one being that we can now show that nontrivial amortization is necessary in erasure channel

FPGA-based stereo vision system for autonomous driving

The project consists on the design and implementation of a real-time stereo vision image sensor oriented to autonomous driving systems using an FPGA. The function of this sensor is to output a real-time depth image from an input of two grayscale luminance images, which can make further processing much easier and faster. The final objective of the project is to develop a standalone prototype for the implementation of the system on an autonomous vehicle, but it will be developed on an existing FPGA platform to prove its viability. Two low-cost digital cameras will be used as input sensors, and the output image will be transmitted to a PC

Compressed Representations of Macromolecular Structures and Properties

SummaryWe introduce a new and unified, compressed volumetric representation for macromolecular structures at varying feature resolutions, as well as for many computed associated properties. Important caveats of this compressed representation are fast random data access and decompression operations. Many computational tasks for manipulating large structures, including those requiring interactivity such as real-time visualization, are greatly enhanced by utilizing this compact representation. The compression scheme is obtained by using a custom designed hierarchical wavelet basis construction. Due to the continuity offered by these wavelets, we retain very good accuracy of molecular surfaces, at very high compression ratios, for macromolecular structures at multiple resolutions

A comprehensive review of tic disorders in children

Tics are characterized by sudden, rapid, recurrent, nonrhythmic movement or vocalization, and are the most common movement disorders in children. Their onset is usually in childhood and tics often will diminish within one year. However, some of the tics can persist and cause various problems such as social embarrassment, physical discomfort, or emotional impairments, which could interfere with daily activities and school performance. Furthermore, tic disorders are frequently associated with comorbid neuropsychiatric symptoms, which can become more problematic than tic symptoms. Unfortunately, misunderstanding and misconceptions of tic disorders still exist among the general population. Understanding tic disorders and their comorbidities is important to deliver appropriate care to patients with tics. Several studies have been conducted to elucidate the clinical course, epidemiology, and pathophysiology of tics, but they are still not well understood. This article aims to provide an overview about tics and tic disorders, and recent findings on tic disorders including history, definition, diagnosis, epidemiology, etiology, diagnostic approach, comorbidities, treatment and management, and differential diagnosis

Trading quantum for classical resources in quantum data compression

We study the visible compression of a source E of pure quantum signal states, or, more formally, the minimal resources per signal required to represent arbitrarily long strings of signals with arbitrarily high fidelity, when the compressor is given the identity of the input state sequence as classical information. According to the quantum source coding theorem, the optimal quantum rate is the von Neumann entropy S(E) qubits per signal. We develop a refinement of this theorem in order to analyze the situation in which the states are coded into classical and quantum bits that are quantified separately. This leads to a trade--off curve Q(R), where Q(R) qubits per signal is the optimal quantum rate for a given classical rate of R bits per signal. Our main result is an explicit characterization of this trade--off function by a simple formula in terms of only single signal, perfect fidelity encodings of the source. We give a thorough discussion of many further mathematical properties of our formula, including an analysis of its behavior for group covariant sources and a generalization to sources with continuously parameterized states. We also show that our result leads to a number of corollaries characterizing the trade--off between information gain and state disturbance for quantum sources. In addition, we indicate how our techniques also provide a solution to the so--called remote state preparation problem. Finally, we develop a probability--free version of our main result which may be interpreted as an answer to the question: ``How many classical bits does a qubit cost?'' This theorem provides a type of dual to Holevo's theorem, insofar as the latter characterizes the cost of coding classical bits into qubits.Comment: 51 pages, 7 figure