$doc.title
... We have shown that the only way the unitary operators U can reproduce the multiplication law for the classical rotations R is if the infinitesimal generators in each case satisfy the same commutation relations, apart from conventional factors of i and h̄. Therefore we adopt the following strategy in ...
... We have shown that the only way the unitary operators U can reproduce the multiplication law for the classical rotations R is if the infinitesimal generators in each case satisfy the same commutation relations, apart from conventional factors of i and h̄. Therefore we adopt the following strategy in ...
Quantum Mechanics for Pedestrians 1: Fundamentals
... has shown that at the start of the lectures, some students do not have enough substantial and available knowledge at their disposal. This applies less to physical and more to the necessary mathematical knowledge, and there are certainly several reasons for this. One of them may be that for teacher t ...
... has shown that at the start of the lectures, some students do not have enough substantial and available knowledge at their disposal. This applies less to physical and more to the necessary mathematical knowledge, and there are certainly several reasons for this. One of them may be that for teacher t ...
Coherence and Spin in GaAs Quantum Dots
... This thesis describes a number of experiments performed in quantum dots as well as 2D systems fabricated in GaAs/AlGaAs 2D electron gases. The focus of the studies is set on spin, coherence and interaction effects of electrons in mesoscopic structures. Experiments investigating the rich physics of sp ...
... This thesis describes a number of experiments performed in quantum dots as well as 2D systems fabricated in GaAs/AlGaAs 2D electron gases. The focus of the studies is set on spin, coherence and interaction effects of electrons in mesoscopic structures. Experiments investigating the rich physics of sp ...
Quantum simulation of disordered systems with cold atoms
... metal-insulator transition, which is the main subject of the present work. The kicked rotor is a paradigm of Hamiltonian classical and quantum chaos. The classical version of this simple system displays a wealth of dynamic behaviors; which makes it well adapted for studies of quantum chaos. Surprisi ...
... metal-insulator transition, which is the main subject of the present work. The kicked rotor is a paradigm of Hamiltonian classical and quantum chaos. The classical version of this simple system displays a wealth of dynamic behaviors; which makes it well adapted for studies of quantum chaos. Surprisi ...
Understanding the effects of leakage in superconducting quantum-error-detection circuits hosh, wler, Martinis,
... there exists a finite probability that the population tunnels out of the computational subspace, a phenomenon often referred to as leakage [1–3]. Understanding the effects of leakage is important for superconducting qubits not only because higher-energy states |2,|3, . . . are present [4,5], as is ...
... there exists a finite probability that the population tunnels out of the computational subspace, a phenomenon often referred to as leakage [1–3]. Understanding the effects of leakage is important for superconducting qubits not only because higher-energy states |2,|3, . . . are present [4,5], as is ...
Transport Properties of Interacting Edge Modes in 2D Topological
... the second corresponds to the existence of topologically protected edge states, vulgo a quantum spin Hall insulator. From another persepective, we see, that the topologically trivial and non-trivial cases are distinguished by whether the chemical potential crosses the bands an even or and odd number ...
... the second corresponds to the existence of topologically protected edge states, vulgo a quantum spin Hall insulator. From another persepective, we see, that the topologically trivial and non-trivial cases are distinguished by whether the chemical potential crosses the bands an even or and odd number ...
Quantum Bianchi I model: an attempt to understand very early
... Introduction As you probably know: Cosmology is devoted to Universe as a whole. Gravitational field plays crucial role in large distances. Einstein’s General Relativity (GR) is a theory of gravity. In fact we can say that cosmology bases on GR. Unfortunatelly GR is a very difficult theory (due to n ...
... Introduction As you probably know: Cosmology is devoted to Universe as a whole. Gravitational field plays crucial role in large distances. Einstein’s General Relativity (GR) is a theory of gravity. In fact we can say that cosmology bases on GR. Unfortunatelly GR is a very difficult theory (due to n ...
Griffiths singularities in the disordered phase of a quantum Ising... H. Rieger
... in pure systems, is that rare regions, which are more strongly correlated than the average, can play a significant role. For classical magnetic systems, Griffiths1 showed that such regions lead to a free energy which is a nonanalytic function of the magnetic field at temperatures below the transitio ...
... in pure systems, is that rare regions, which are more strongly correlated than the average, can play a significant role. For classical magnetic systems, Griffiths1 showed that such regions lead to a free energy which is a nonanalytic function of the magnetic field at temperatures below the transitio ...
Bohr`s Complementarity and Kant`s Epistemology
... term of the cognitive relation. Let us now turn to the other, objective term of the relation. Beyond the horizon of experience, in the region denoted by the term ‘transcendent’, lies, according to Kant, the ideally conceived ‘thing in itself’, that is, the thing as it is independently of any relatio ...
... term of the cognitive relation. Let us now turn to the other, objective term of the relation. Beyond the horizon of experience, in the region denoted by the term ‘transcendent’, lies, according to Kant, the ideally conceived ‘thing in itself’, that is, the thing as it is independently of any relatio ...
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.