Quantum information processing with superconducting qubits in a
... attention because quantum computers are expected to be capable of performing certain tasks which no classical computers can do in practical time scales. Early proposals for quantum computers were mainly based on quantum optical systems, such as those utilizing lasercooled trapped ions [1, 2], photon ...
... attention because quantum computers are expected to be capable of performing certain tasks which no classical computers can do in practical time scales. Early proposals for quantum computers were mainly based on quantum optical systems, such as those utilizing lasercooled trapped ions [1, 2], photon ...
Seeing a single photon without destroying it
... Light detection is usually a destructive process, in that detectors annihilate photons and convert them into electrical signals, making it impossible to see a single photon twice. But this limitation is not fundamentalÐquantum non-demolition strategies1±3 permit repeated measurements of physically o ...
... Light detection is usually a destructive process, in that detectors annihilate photons and convert them into electrical signals, making it impossible to see a single photon twice. But this limitation is not fundamentalÐquantum non-demolition strategies1±3 permit repeated measurements of physically o ...
1 Introduction and Disclaimer
... We will sketch the computation by Maulik and Okounkov of the quantum cohomology of Hilbn C2 . As you will see, the proof is somewhat indirect, but the methods used apply to general quiver varieties, and yield a variety of other great results. See [3] for a more direct proof. Due to limitations in sp ...
... We will sketch the computation by Maulik and Okounkov of the quantum cohomology of Hilbn C2 . As you will see, the proof is somewhat indirect, but the methods used apply to general quiver varieties, and yield a variety of other great results. See [3] for a more direct proof. Due to limitations in sp ...
Document
... • The (simplest) example involves the most extreme nonlocal box, the PR box. But any nonlocal box violating Tsirelson’s bound violates information causality. • So are we done? No, because the correlations of some nonlocal boxes (“noisy” nonlocal boxes) do not exceed Tsirelson’s bound yet are not qua ...
... • The (simplest) example involves the most extreme nonlocal box, the PR box. But any nonlocal box violating Tsirelson’s bound violates information causality. • So are we done? No, because the correlations of some nonlocal boxes (“noisy” nonlocal boxes) do not exceed Tsirelson’s bound yet are not qua ...
Abstracts - Weizmann Institute of Science
... question: Given an interacting particle system are the stationary measures of the dynamics stable to small (extensive) perturbations? In general, there is no reason to believe this is so and one must restrict the class of models under consideration in one way or another. As such, I will focus in thi ...
... question: Given an interacting particle system are the stationary measures of the dynamics stable to small (extensive) perturbations? In general, there is no reason to believe this is so and one must restrict the class of models under consideration in one way or another. As such, I will focus in thi ...
Quantum error correcting codes and Weyl commutation relations
... classical error correcting codes. In section 2 we have seen that N -correcting quantum codes are described by projections obeying the Knill-Laflamme property (2.2). Projections can be viewed as averages of group representations. For a given projection of this kind we can describe the errors that it ...
... classical error correcting codes. In section 2 we have seen that N -correcting quantum codes are described by projections obeying the Knill-Laflamme property (2.2). Projections can be viewed as averages of group representations. For a given projection of this kind we can describe the errors that it ...
Components of the Atom
... The Bohr Theory of the atom (“Old” Quantum Mechanics) works perfectly for H (as well as He+, Li2+, etc.). And it’s so much EASIER than the Schrödinger Equation. The only problem with the Bohr Theory is that it fails as soon as you try to use it on an atom as “complex” as helium. ...
... The Bohr Theory of the atom (“Old” Quantum Mechanics) works perfectly for H (as well as He+, Li2+, etc.). And it’s so much EASIER than the Schrödinger Equation. The only problem with the Bohr Theory is that it fails as soon as you try to use it on an atom as “complex” as helium. ...
Modern Physics: Quantum Mechanics
... Modern Physics: Quantum Mechanics • Physics changed drastically in the early 1900’s • New discoveries — Relativity and Quantum Mechanics • Relativity – Changed the way we think about space and time ...
... Modern Physics: Quantum Mechanics • Physics changed drastically in the early 1900’s • New discoveries — Relativity and Quantum Mechanics • Relativity – Changed the way we think about space and time ...
1 Classical Mechanics
... atomic spectral lines, the spectral distribution of black body radiation, chemical reactions, etc. Nevertheless, classical and quantum mechanics are closely connected. Just as geometrical optics can be regarded as the short wavelength limit of wave optics, so classical mechanics can be regarded as t ...
... atomic spectral lines, the spectral distribution of black body radiation, chemical reactions, etc. Nevertheless, classical and quantum mechanics are closely connected. Just as geometrical optics can be regarded as the short wavelength limit of wave optics, so classical mechanics can be regarded as t ...
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.