More Graviton Physics
... The calculation of photon interactions with matter is part of any introductory (or advanced) course on quantum mechanics. Indeed the evaluation of the Compton scattering cross section is a standard exercise in relativistic quantum mechanics, since gauge invariance together with the masslessness of t ...
... The calculation of photon interactions with matter is part of any introductory (or advanced) course on quantum mechanics. Indeed the evaluation of the Compton scattering cross section is a standard exercise in relativistic quantum mechanics, since gauge invariance together with the masslessness of t ...
Quantum Correlations in Optical Angle–Orbital Angular Momentum
... tum mechanics is incomplete, in that systems possess additional hidden variables, or that quantum mechanics is nonlocal, in that measurement of the position or momentum of either particle results in an instantaneous uncertainty of the momentum or position, respectively, of both (2). In 1964, Bell de ...
... tum mechanics is incomplete, in that systems possess additional hidden variables, or that quantum mechanics is nonlocal, in that measurement of the position or momentum of either particle results in an instantaneous uncertainty of the momentum or position, respectively, of both (2). In 1964, Bell de ...
Pair Production and the Light-front Vacuum
... special theory of relativity and quantum mechanics in the late 1920s (Dirac, 1927), quantum vacuum has emerged as an extremely interesting medium with remarkable properties to investigate. QED has been extremely successful in explaining the physical phenomena involving the interaction between light ...
... special theory of relativity and quantum mechanics in the late 1920s (Dirac, 1927), quantum vacuum has emerged as an extremely interesting medium with remarkable properties to investigate. QED has been extremely successful in explaining the physical phenomena involving the interaction between light ...
Quantum Theory of Molecular Magnetism - cond
... In this chapter I would like to present a short introduction into the field of molecular magnetism and some of the theoretical techniques as well as results. Some parts of the presentation overlap with earlier presentations in Refs. [1, 2]. The synthesis of magnetic molecules shows continuous progre ...
... In this chapter I would like to present a short introduction into the field of molecular magnetism and some of the theoretical techniques as well as results. Some parts of the presentation overlap with earlier presentations in Refs. [1, 2]. The synthesis of magnetic molecules shows continuous progre ...
Observations on Hyperplane: II. Dynamical Variables and
... observables at time, t = 0) would be a crazy way to do physics, said I! No it wouldn't, said he. Circumstances then intervened and the discussion ended, never to be resumed. I will here explain why I claimed it would be a crazy way to do physics. Why, in fact, it would be an impossible way to actual ...
... observables at time, t = 0) would be a crazy way to do physics, said I! No it wouldn't, said he. Circumstances then intervened and the discussion ended, never to be resumed. I will here explain why I claimed it would be a crazy way to do physics. Why, in fact, it would be an impossible way to actual ...
Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits M. D. Shulman
... splitting, J , between |S〉 and |T0 〉, and rotations around the x-axis are driven by a magnetic field gradient, ∆B z between the electrons. We implement the S-T0 qubit by confining two electrons to a double quantum dot (QD) in a two dimensional electron gas (2DEG) located 91nm below the surface of a ...
... splitting, J , between |S〉 and |T0 〉, and rotations around the x-axis are driven by a magnetic field gradient, ∆B z between the electrons. We implement the S-T0 qubit by confining two electrons to a double quantum dot (QD) in a two dimensional electron gas (2DEG) located 91nm below the surface of a ...
Observation of Distinct Two-Photon Transition Channels in CdTe
... confined electron-hole system. Such tight spatial confinement provides interesting optical features, such as size-tunable absorption and emission, which are closely associated with new technologies spanning from biology to physics [1–15]. The optical properties of QDs are described by quantum mechan ...
... confined electron-hole system. Such tight spatial confinement provides interesting optical features, such as size-tunable absorption and emission, which are closely associated with new technologies spanning from biology to physics [1–15]. The optical properties of QDs are described by quantum mechan ...
Quixotic Order and Broken Symmetry in the Quantum Hall Effect and
... First of all, I’d like to thank my adviser, Shivaji Sondhi. From our first conversation as I contemplated taking the plunge into condensed matter, he has been a steady source of encouragement, and his dry humor and thoughtful criticism have made the growing pains of graduate school easier to bear. Sh ...
... First of all, I’d like to thank my adviser, Shivaji Sondhi. From our first conversation as I contemplated taking the plunge into condensed matter, he has been a steady source of encouragement, and his dry humor and thoughtful criticism have made the growing pains of graduate school easier to bear. Sh ...
Quantum scattering
... Therefore, the task of constructing the semiclassics of a scattering system is completed, if we can find a connection between the spectral density d(E) and the scattering matrix S . We will see that (35.12) provides the clue. Note that the right hand side of (35.12) has nearly the structure of (35.1 ...
... Therefore, the task of constructing the semiclassics of a scattering system is completed, if we can find a connection between the spectral density d(E) and the scattering matrix S . We will see that (35.12) provides the clue. Note that the right hand side of (35.12) has nearly the structure of (35.1 ...
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.