Non-Markovian disentanglement dynamics of two-qubit system

We investigated the disentanglement dynamics of two-qubit system in Non-Markovian approach. We showed that only the couple strength with the environment near to or less than fine-structure constant 1/137, entanglement appear exponential decay for a certain class of two-qubit entangled state. While the coupling between qubit and the environment is much larger, system always appears the sudden-death of entanglement even in the vacuum environment.Comment: 17 pages, 3 figure

Sistem Peringatan Dini Akan Bahaya Kebakaran

Fire disaster is one from many other disasters that very dangerous because not only it's took heavy financial and material loss, but also often takes lives. For this reason, it needs the system which can give early warning not only to the people around the building but also to the building owner. This system must also work to delay fire spreading. This paper discuss the designing and implementation of early warning system to help minimize loss from fire disaster

Sistem Pemantauan dan Pengendalian Parameter Lingkungan Pertumbuhan pada Tanaman Hidroponik

Lingkungan sebagai bagian dari kehidupan mahluk hidup memiliki pengaruh besar terhadap tumbuh kembang tanaman. Penelitian yang mempelajari tumbuh kembang tanaman terus berlangsung hingga saat ini, misalnya untuk memperoleh formulasi optimal bagi tumbuh kembang tanaman yang diterapkan pada tanaman hidroponik. Penelitian dilakukan dengan memantau, merekam dan memberikan suatu perlakuan bagi tanaman. Perancangan ini bertujuan untuk melakukan pemantauan, perekaman, dan pengendalian parameter lingkungan pertumbuhan secara otomatis, sehingga membantu penelitian mengenai tumbuh kembang tanaman. Sistem ini berkerja memantau dan mengendalikan parameter lingkungan pertumbuhan dengan sensor, mikrokontroler, dan pengendali parameter sesuai batas yang ditentukan oleh pengguna dan merekam serta menampilkan data hasil pemantauan parameter yang telah dilakukan dengan grafik pada komputer. Berdasarkan pengujian, sistem berhasil memantau, merekam, dan mengendalikan parameter lingkungan selama sistem beroperasi

Scaling properties of a low-actuation pressure microfluidic valve

Using basic physical arguments, we present a design and method for the fabrication of microfluidic valves using multilayer soft lithography. These on-off valves have extremely low actuation pressures and can be used to fabricate active functions, such as pumps and mixers in integrated microfluidic chips. We characterized the performance of the valves by measuring both the actuation pressure and flow resistance over a wide range of design parameters, and compared them to both finite element simulations and alternative valve geometries

Security proof of a three-state quantum key distribution protocol without rotational symmetry

Standard security proofs of quantum key distribution (QKD) protocols often rely on symmetry arguments. In this paper, we prove the security of a three-state protocol that does not possess rotational symmetry. The three-state QKD protocol we consider involves three qubit states, where the first two states, |0_z> and |1_z>, can contribute to key generation and the third state, |+>=(|0_z>+|1_z>)/\sqrt{2}, is for channel estimation. This protocol has been proposed and implemented experimentally in some frequency-based QKD systems where the three states can be prepared easily. Thus, by founding on the security of this three-state protocol, we prove that these QKD schemes are, in fact, unconditionally secure against any attacks allowed by quantum mechanics. The main task in our proof is to upper bound the phase error rate of the qubits given the bit error rates observed. Unconditional security can then be proved not only for the ideal case of a single-photon source and perfect detectors, but also for the realistic case of a phase-randomized weak coherent light source and imperfect threshold detectors. Our result on the phase error rate upper bound is independent of the loss in the channel. Also, we compare the three-state protocol with the BB84 protocol. For the single-photon source case, our result proves that the BB84 protocol strictly tolerates a higher quantum bit error rate than the three-state protocol; while for the coherent-source case, the BB84 protocol achieves a higher key generation rate and secure distance than the three-state protocol when a decoy-state method is used.Comment: 10 pages, 3 figures, 2 column

Effects of Zeeman spin splitting on the modular symmetry in the quantum Hall effect

Magnetic-field-induced phase transitions in the integer quantum Hall effect are studied under the formation of paired Landau bands arising from Zeeman spin splitting. By investigating features of modular symmetry, we showed that modifications to the particle-hole transformation should be considered under the coupling between the paired Landau bands. Our study indicates that such a transformation should be modified either when the Zeeman gap is much smaller than the cyclotron gap, or when these two gaps are comparable.Comment: 8 pages, 4 figure

Macroscopic Quantum Phase Interference in Antiferromagnetic Particles

The tunnel splitting in biaxial antiferromagnetic particles is studied with a magnetic field applied along the hard anisotropy axis. We observe the oscillation of tunnel splitting as a function of the magnetic field due to the quantum phase interference of two tunneling paths of opposite windings. The oscillation is similar to the recent experimental result with Fe}$_8$\textrm{\ molecular clusters.}Comment: 8 pages, 2 postscript figures, to appear in J. Phys.: Condes. Matte

Tunnel splitting and quantum phase interference in biaxial ferrimagnetic particles at excited states

The tunneling splitting in biaxial ferrimagnetic particles at excited states with an explicit calculation of the prefactor of exponent is obtained in terms of periodic instantons which are responsible for tunneling at excited states and is shown as a function of magnetic field applied along an arbitrary direction in the plane of hard and medium axes. Using complex time path-integral we demonstrate the oscillation of tunnel splitting with respect to the magnitude and the direction of the magnetic field due to the quantum phase interference of two tunneling paths of opposite windings . The oscillation is gradually smeared and in the end the tunnel splitting monotonously increases with the magnitude of the magnetic field when the direction of the magnetic field tends to the medium axis. The oscillation behavior is similar to the recent experimental observation with Fe$_8$ molecular clusters. A candidate of possible experiments to observe the effect of quantum phase interference in the ferrimagnetic particles is proposed.Comment: 15 pages, 5 figures, acceptted to be pubblished in Physical Review

Development of Building Heat Detection System: An Improvement Study

ABSTRACT- The increment of the numbers for accidents due to building safety system errors has created a serious disaster over the year. Due to that reason, this paper presents the entitled Building Heat Detection System (BHD System) by the objectives to develop the proper circuit in order to secure the detection device during the building fire attack. A BHD system, also known as fire protection system consists of heat sensing and monitoring system. The sensors detect extreme heat in an area or zone; the control unit processes the signals and sets off evacuation alarms to alert building occupants. This study focused on the design and fabrication of the system prototype to demonstrate the operation of a BHD system in case of fire accidents. Hose reel indicator is included to display the exact location in a building to aid in firefighting. On top of that, exit indicators were added to show the available exits should fire breaks out in a building. This study is hoped to help the system engineers to improve and secure their building safety system in the future