A scheme for efficient quantum computation with linear optics
... computation is possible using only beam splitters, phase shifters, single photon sources and photo-detectors. Our methods exploit feedback from photo-detectors and are robust against errors from photon loss and detector inef®ciency. The basic elements are accessible to experimental investigation wit ...
... computation is possible using only beam splitters, phase shifters, single photon sources and photo-detectors. Our methods exploit feedback from photo-detectors and are robust against errors from photon loss and detector inef®ciency. The basic elements are accessible to experimental investigation wit ...
The Learnability of Quantum States
... numerical simulations to check experimentally that the learning theorem is true ...
... numerical simulations to check experimentally that the learning theorem is true ...
Design and proof of concept for silicon-based quantum dot
... Figure 3 provides insight into the operation of the device. Results are shown for two configurations of the gate voltages, corresponding to points A and B in Fig. 2. For case A, corresponding to a low barrier ( | Vin | << | Vout | ), the potential landscape becomes an elongated trough, with signific ...
... Figure 3 provides insight into the operation of the device. Results are shown for two configurations of the gate voltages, corresponding to points A and B in Fig. 2. For case A, corresponding to a low barrier ( | Vin | << | Vout | ), the potential landscape becomes an elongated trough, with signific ...
... to the orbit types of the group action, the manifold is stratified into different strata. Mechanics will be set up on each stratum and then reduced by symmetry. We apply this idea, taking M and G as the center-of-mass system for N bodies and the rotation group SO(3), respectively. The center-of-mass ...
Gravity and dark energy from quantum information
... Mod.Phys.Lett.A25:257-267,2010 Dark energy is cosmic Hawking radiation ...
... Mod.Phys.Lett.A25:257-267,2010 Dark energy is cosmic Hawking radiation ...
Topological Quantum Computation from non-abelian anyons
... Namely, when the overall channel is I , when the combination of anyons 1 and 2 fuses to state φ, then anyons 3 and 4 must also be in the state φ. If anyons 1 and 2 fuse to I , then anyons 3 and 4 must also fuse to I . ...
... Namely, when the overall channel is I , when the combination of anyons 1 and 2 fuses to state φ, then anyons 3 and 4 must also be in the state φ. If anyons 1 and 2 fuse to I , then anyons 3 and 4 must also fuse to I . ...
High Performance Quantum Computing
... mirror 4. The photo detectors see the photon only in one place: random selection photon source ...
... mirror 4. The photo detectors see the photon only in one place: random selection photon source ...
ppt - ICTS
... moments of a quantum reference frame. We give recursive equations (Theorem 2) for how the moments evolve with the number of uses of the quantum reference frame. We derive sufficient conditions (Theorem 3) for the longevity of a quantum reference frame to scale by a factor proportional to square ...
... moments of a quantum reference frame. We give recursive equations (Theorem 2) for how the moments evolve with the number of uses of the quantum reference frame. We derive sufficient conditions (Theorem 3) for the longevity of a quantum reference frame to scale by a factor proportional to square ...
The quantum does not reduce to discrete bits
... matter — you mostly find empty space. Your hand, your chair, the floor … it's all made up of mostly of nothing. John Archibald Wheeler took this idea to its logical conclusion, and suggested that matter may only have an information content, and no substance at all. Even those electrons and quarks ma ...
... matter — you mostly find empty space. Your hand, your chair, the floor … it's all made up of mostly of nothing. John Archibald Wheeler took this idea to its logical conclusion, and suggested that matter may only have an information content, and no substance at all. Even those electrons and quarks ma ...
Quantum spin system with on-site exchange in a magnetic field G. P
... the exchange interaction and D is the single-ion anisotropy. Formally, the Hamiltonian (3) can be rewritten into the equivalent form in terms of spin –1/2. Let us express each spin Si over the sum Si = σ iA + σ iB of two classical spins σ iα = ±1/ 2 on the ith site. This transformation is non-one-t ...
... the exchange interaction and D is the single-ion anisotropy. Formally, the Hamiltonian (3) can be rewritten into the equivalent form in terms of spin –1/2. Let us express each spin Si over the sum Si = σ iA + σ iB of two classical spins σ iα = ±1/ 2 on the ith site. This transformation is non-one-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.