Power of Quantum Computation with Few Clean Qubits

This paper investigates the power of polynomial-time quantum computation in which only a very limited number of qubits are initially clean in the |0> state, and all the remaining qubits are initially in the totally mixed state. No initializations of qubits are allowed during the computation, nor intermediate measurements. The main results of this paper are unexpectedly strong error-reducible properties of such quantum computations. It is proved that any problem solvable by a polynomial-time quantum computation with one-sided bounded error that uses logarithmically many clean qubits can also be solvable with exponentially small one-sided error using just two clean qubits, and with polynomially small one-sided error using just one clean qubit. It is further proved in the case of two-sided bounded error that any problem solvable by such a computation with a constant gap between completeness and soundness using logarithmically many clean qubits can also be solvable with exponentially small two-sided error using just two clean qubits. If only one clean qubit is available, the problem is again still solvable with exponentially small error in one of the completeness and soundness and polynomially small error in the other. As an immediate consequence of the above result for the two-sided-error case, it follows that the TRACE ESTIMATION problem defined with fixed constant threshold parameters is complete for the classes of problems solvable by polynomial-time quantum computations with completeness 2/3 and soundness 1/3 using logarithmically many clean qubits and just one clean qubit. The techniques used for proving the error-reduction results may be of independent interest in themselves, and one of the technical tools can also be used to show the hardness of weak classical simulations of one-clean-qubit computations (i.e., DQC1 computations).Comment: 44 pages + cover page; the results in Section 8 are overlapping with the main results in arXiv:1409.677

Perception analysis of living environment at Taman Melati residential area

Rapid physical development in a residential area will deteriorate living environment of the residents especially if it takes place haphazardly without applying adequate planning guidelines. It will, eventually, exert more pressure on physical infrastructure of the area. As a result, residents of the area will be subjected to dissatisfaction on the present supporting infrastructure as the demand exceeds the supply. Evidently, it may lead to poor living conditions of the area, which ultimately slow the progressiveness of the society to achieve the quality of living standards. This paper investigates residents’ perceptions on present living environmental setting at Taman Melati residential area in Kuala Lumpur. Questionnaire survey was administered to determine the perceptions of the residents on physical environmental parameters such as air, noise, streetlight illuminance, and traffic volume. The level of satisfaction of the residents on the living environment had showed nearly 64% of the respondents expressed “satisfied strongly” or “satisfied”. The level of willingness of the residents to stay further continuously at Taman Melati indicates about 56% of the respondents expressed “strongly willing” or “willing”. It is also seen that the overall satisfaction level of the residents on the living environment was high albeit satisfaction level on individual physical environmental parameters was low

Influence of the step number of the approach run on the jumping kinematics in volleyball spike jumps

Topics in Exercise Science and Kinesiology Volume 4: Issue 1, Article 15, 2023. In volleyball, the approach run serves as a strategy to execute a spike from an elevated striking position. Nevertheless, the influence of the step number of the approach run on the jumping kinematics in spike jumps is unclear. Therefore, this investigation aims to clarify the impact of varying step numbers within the approach run on jumping kinematics. Seven female volleyball athletes were tasked with executing spike jumps, employing 2 and 3-step approach runs. These trials were recorded using high-speed cameras and digitized, and then the kinematics of the 2 and 3-step trials were compared. The findings of this study unveiled that, in the 3-step trial with higher horizontal velocity, the center of gravity was upheld at an elevated level, thereby curtailing the vertical displacement of the center of gravity from the last step before the takeoff to the takeoff. Within the 2-step trial, a notable deceleration of horizontal velocity in the first half of the takeoff was virtually absent. However, the 3-step trial with higher horizontal velocity entailed more flexion of the dominant knee joint to decelerate the horizontal velocity during the first half. Furthermore, the 3-step trial entails a swifter extension of the hip, knee, and ankle joints of the non-dominant leg. This accelerated extension likely contributes to an augmented vertical velocity at the foot release of the takeoff

Ladder Siamese Network: a Method and Insights for Multi-level Self-Supervised Learning

Siamese-network-based self-supervised learning (SSL) suffers from slow convergence and instability in training. To alleviate this, we propose a framework to exploit intermediate self-supervisions in each stage of deep nets, called the Ladder Siamese Network. Our self-supervised losses encourage the intermediate layers to be consistent with different data augmentations to single samples, which facilitates training progress and enhances the discriminative ability of the intermediate layers themselves. While some existing work has already utilized multi-level self supervisions in SSL, ours is different in that 1) we reveal its usefulness with non-contrastive Siamese frameworks in both theoretical and empirical viewpoints, and 2) ours improves image-level classification, instance-level detection, and pixel-level segmentation simultaneously. Experiments show that the proposed framework can improve BYOL baselines by 1.0% points in ImageNet linear classification, 1.2% points in COCO detection, and 3.1% points in PASCAL VOC segmentation. In comparison with the state-of-the-art methods, our Ladder-based model achieves competitive and balanced performances in all tested benchmarks without causing large degradation in one

PdBr2‐Catalyzed Acetal Formation of Carbonyl Compounds Using Diazophenanthrenequinone: Utility of 9,10‐Phenanthrenedioxyacetal

We developed a new acetalization method of ketones and aldehydes under non-acidic conditions using diazophenanthrenequinone and PdBr2. The formed acetals that have a phenanthrene skeleton withstand under mild acidic conditions. Removal of acetals was successfully proceeded under strong acidic or oxidation conditions using aqueous ceric ammonium nitrate (CAN) to afford corresponding ketones and aldehydes

Retrospective analysis of definitive radiotherapy for neck node metastasis from unknown primary tumor: Japanese Radiation Oncology Study Group study

Objective: To investigate the optimal treatment method and risk factor of neck node metastasis from unknown primary tumors (NUP) treated by radiotherapy. Methods: Retrospective case study based on a multi-institutional survey was conducted by the Japanese Radiation Oncology Study Group. Patients pathologically diagnosed as having NUP from 1998 to 2007 were identified. Univariate and multivariate analyses of overall survival (OS), progression free survival (PFS), neck progression free survival (NPFS) and mucosal progression free survival (MPFS) were evaluated. Results: In total, 130 patients with median age of 65 years were included. Nodal stages N1, N2a, N2b and N2c were observed for 10, 26, 43, 12 and 39 patients, respectively. All the patients received radiotherapy (RT) with neck dissection in 60 and with chemotherapy in 67 cases. The median doses to the metastatic nodes, prophylactic neck and prophylactic mucosal sites were 60.0, 50.4 and 50.4 Gy, respectively. The median follow-up period for surviving patients was 42 months. Among 12 patients, occult primary tumors in the neck region developed after radiotherapy. The 5-year OS, PFS, NPFS and MPFS were 58.1%, 42.4%, 47.3% and 54.9%, respectively. Univariate analysis showed that lower N stage (N1?2b), non-bulky node (<6 cm) and negative extracapsular extension (ECE) status were the factors associated with favorable OS, PFS, NPFS and MPFS. Radical surgery proved to be a favorable factor of OS, NPFS and MPFS. On multivariate analysis, lower N stage and negative ECE status were correlated with improved survival. Conclusions: Lower nodal stage and negative ECE status showed a favorable impact on survival and disease control in patients with NUP treated by radiotherapy

Relationship between winter ice redistribution and summer ice extent in the Arctic

第2回極域科学シンポジウム　共通セッション「大気-海洋-雪氷-固体地球の相互作用」 11月15日（火） 統計数理研究所 3階セミナー室