Quantum Transport Theory with Tight-Binding Hamiltonian Stefano Sanvito Department of Physics
... Now, one defines the projector P as before, and the scattering coefficients are computed. ...
... Now, one defines the projector P as before, and the scattering coefficients are computed. ...
(2)
... equation cannot be solved for the large number of degrees of freedom in the subsystem and its environment. Often the environment 共also referred to as the bath兲 may be treated classically to a good approximation while the quantum character of the subsystem is essential for a description of its proper ...
... equation cannot be solved for the large number of degrees of freedom in the subsystem and its environment. Often the environment 共also referred to as the bath兲 may be treated classically to a good approximation while the quantum character of the subsystem is essential for a description of its proper ...
PPT1
... If a system is not fully prepared (e.g. in a thermal state or in the presence of decoherence) classical uncertainty about the state of the system is present in addition to the quantum nature contained in |i. In these situations only the (classical) probability pi for the system occupying the state ...
... If a system is not fully prepared (e.g. in a thermal state or in the presence of decoherence) classical uncertainty about the state of the system is present in addition to the quantum nature contained in |i. In these situations only the (classical) probability pi for the system occupying the state ...
Partial Observation of Quantum Turing Machine and Weaker Well
... After a brief introduction to quantum basics (see [9] for a complete introduction), we introduce in section 4, such a less restrictive class of quantum Turing machines, the observable quantum Turing machines (OQTM), where partial observations can be performed at each transition. Fondamentals of OQT ...
... After a brief introduction to quantum basics (see [9] for a complete introduction), we introduce in section 4, such a less restrictive class of quantum Turing machines, the observable quantum Turing machines (OQTM), where partial observations can be performed at each transition. Fondamentals of OQT ...
Very brief introduction to Conformal Field Theory
... The chiral correlators can be obtained from those of the Ising model ...
... The chiral correlators can be obtained from those of the Ising model ...
Quantum fluctuations and the Casimir effect
... keep the ratio between old shot-noise and the amplified signal constant, and not much smaller than unity. In this way the new shot-noise, the one that appears due to the coupling with the signal, will be of the same order of the old shot-noise and the amplified signal and not much larger. ...
... keep the ratio between old shot-noise and the amplified signal constant, and not much smaller than unity. In this way the new shot-noise, the one that appears due to the coupling with the signal, will be of the same order of the old shot-noise and the amplified signal and not much larger. ...
Quantum Interference of Molecules
... history. Is light a wave or is it made up of particles? The earliest theory on the nature of light goes back to the corpuscular theory of Newton in 1704. Though Christian Huygens had proposed the wave theory of light in 1690, Newton's corpuscular theory, according to which light is composed of tiny ...
... history. Is light a wave or is it made up of particles? The earliest theory on the nature of light goes back to the corpuscular theory of Newton in 1704. Though Christian Huygens had proposed the wave theory of light in 1690, Newton's corpuscular theory, according to which light is composed of tiny ...
Control of
... 4. But classical mechanics does not show interference based control – hence decoherence can be expected to cause loss of control. Thus understanding of the control of systems in a bath relates to an understanding of the classical limit, and what happens in the classical limit. In particular, we ask: ...
... 4. But classical mechanics does not show interference based control – hence decoherence can be expected to cause loss of control. Thus understanding of the control of systems in a bath relates to an understanding of the classical limit, and what happens in the classical limit. In particular, we ask: ...
Educação - Química Nova
... The quantum defect δ is well defined for quasi one-electron-atom, e.g., neutral alkaline-metal atoms, singly charged C atoms or for an alkaline-earth cation.12 We consider that it is possible to define an effective quantum defect u for the ground-state of all neutral atoms, similarly to Slater’s cor ...
... The quantum defect δ is well defined for quasi one-electron-atom, e.g., neutral alkaline-metal atoms, singly charged C atoms or for an alkaline-earth cation.12 We consider that it is possible to define an effective quantum defect u for the ground-state of all neutral atoms, similarly to Slater’s cor ...
Some Basic Aspects of Fractional Quantum Numbers
... Therefore the discovery of physical circumstances in which the unit of charge can be fractionated, its quanta dequantized, came as a shock to most physicists. It is remarkable that this fundamental discovery emerged neither from recondite theoretical speculation, nor from experiments at the high-ene ...
... Therefore the discovery of physical circumstances in which the unit of charge can be fractionated, its quanta dequantized, came as a shock to most physicists. It is remarkable that this fundamental discovery emerged neither from recondite theoretical speculation, nor from experiments at the high-ene ...
slides - Mathematics Department
... real problem now is which one of these two exact theories admits a relativistic generalization. I want to quickly mention some attempts to get this. Bohmian mechanics admits relativistic generalizations of various kinds, from the original attempts by Bohm and Hiley dealing with a relativistic theory ...
... real problem now is which one of these two exact theories admits a relativistic generalization. I want to quickly mention some attempts to get this. Bohmian mechanics admits relativistic generalizations of various kinds, from the original attempts by Bohm and Hiley dealing with a relativistic theory ...
Quantum key distribution
Quantum key distribution (QKD) uses quantum mechanics to guarantee secure communication. It enables two parties to produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages. It is often incorrectly called quantum cryptography, as it is the most well known example of the group of quantum cryptographic tasks.An important and unique property of quantum key distribution is the ability of the two communicating users to detect the presence of any third party trying to gain knowledge of the key. This results from a fundamental aspect of quantum mechanics: the process of measuring a quantum system in general disturbs the system. A third party trying to eavesdrop on the key must in some way measure it, thus introducing detectable anomalies. By using quantum superpositions or quantum entanglement and transmitting information in quantum states, a communication system can be implemented which detects eavesdropping. If the level of eavesdropping is below a certain threshold, a key can be produced that is guaranteed to be secure (i.e. the eavesdropper has no information about it), otherwise no secure key is possible and communication is aborted.The security of encryption that uses quantum key distribution relies on the foundations of quantum mechanics, in contrast to traditional public key cryptography which relies on the computational difficulty of certain mathematical functions, and cannot provide any indication of eavesdropping at any point in the communication process, or any mathematical proof as to the actual complexity of reversing the one-way functions used. QKD has provable security based on information theory, and forward secrecy.Quantum key distribution is only used to produce and distribute a key, not to transmit any message data. This key can then be used with any chosen encryption algorithm to encrypt (and decrypt) a message, which can then be transmitted over a standard communication channel. The algorithm most commonly associated with QKD is the one-time pad, as it is provably secure when used with a secret, random key. In real world situations, it is often also used with encryption using symmetric key algorithms like the Advanced Encryption Standard algorithm. In the case of QKD this comparison is based on the assumption of perfect single-photon sources and detectors, that cannot be easily implemented.