Quantum Channel Capacities (PDF Available)
... The foundation of quantum mechanics brought a lot of new observations, like entanglement and uncertainty which seem to be incompatible with our classical intuition, but if we use quantum mechanics as a resource for our purposes we can explore some useful and impressive phenomena. To do so is the goa ...
... The foundation of quantum mechanics brought a lot of new observations, like entanglement and uncertainty which seem to be incompatible with our classical intuition, but if we use quantum mechanics as a resource for our purposes we can explore some useful and impressive phenomena. To do so is the goa ...
RTF format - Huw Price
... tightly constrained trajectories (one particle on each), having perhaps interacted in a specified region at the intersection of these two trajectories (though not with any particle which does not itself emerge on one of these trajectories). We then consider the distribution of initial trajectories, ...
... tightly constrained trajectories (one particle on each), having perhaps interacted in a specified region at the intersection of these two trajectories (though not with any particle which does not itself emerge on one of these trajectories). We then consider the distribution of initial trajectories, ...
Issues in Inflationary and Cyclic Cosmology
... “the (true) quantum perspective” Inflation is dominantly a quantum process… in which (classical) inflation amplifies rare quantum fluctuations… resulting in a peculiar kind of disorder ...
... “the (true) quantum perspective” Inflation is dominantly a quantum process… in which (classical) inflation amplifies rare quantum fluctuations… resulting in a peculiar kind of disorder ...
Single-Photon Bus between Spin-Wave Quantum Memories.
... but heralded generation of a single magnon in macro-atom A, we transfer the magnon (or, if we choose, a portion of it) to macro-atom B while suppressing the population of the photonic mode by means of quantum interference (adiabatic dark-state transfer)24–26 . Successful transfer is verified by subs ...
... but heralded generation of a single magnon in macro-atom A, we transfer the magnon (or, if we choose, a portion of it) to macro-atom B while suppressing the population of the photonic mode by means of quantum interference (adiabatic dark-state transfer)24–26 . Successful transfer is verified by subs ...
Computational Power of the Quantum Turing Automata
... found for which a quantum machine computed the answer with certainty in polynomial time, whereas requiring a probabilistic classical machine to solve the same problem with certainty required exponential time for some inputs. Note, however, that relative to the same oracle, these problems were in BPP ...
... found for which a quantum machine computed the answer with certainty in polynomial time, whereas requiring a probabilistic classical machine to solve the same problem with certainty required exponential time for some inputs. Note, however, that relative to the same oracle, these problems were in BPP ...
Chapter 24 - William Stallings, Data and Computer
... relay of application-level traffic tend to be more secure than packet filters easy to log and audit all incoming traffic Disadvantage: ...
... relay of application-level traffic tend to be more secure than packet filters easy to log and audit all incoming traffic Disadvantage: ...
Unitary time evolution
... preparing another system. But it is impossible to copy an unknown quantum state. This means that many techniques of classical information theory (such as protecting information by making redundant copies, or having a fanout gate from a single bit) are impossible in quantum information theory. ...
... preparing another system. But it is impossible to copy an unknown quantum state. This means that many techniques of classical information theory (such as protecting information by making redundant copies, or having a fanout gate from a single bit) are impossible in quantum information theory. ...
Wednesday, Feb. 7, 2007, at 1 p.m. ET Embargoed for Release:
... Technique may give scientists a new degree of control over fiber‐optic communication and quantum information processing ...
... Technique may give scientists a new degree of control over fiber‐optic communication and quantum information processing ...
Religion and the quantum world Transcript
... We should not, however, confine human freedom to the realm of quantum indeterminacy. Quantum indeterminacies occur at minute dimensions, and normally cancel out over millions of cases, so as to give rise to the orderly world we see around us. The importance of quantum theory is not that it proves t ...
... We should not, however, confine human freedom to the realm of quantum indeterminacy. Quantum indeterminacies occur at minute dimensions, and normally cancel out over millions of cases, so as to give rise to the orderly world we see around us. The importance of quantum theory is not that it proves t ...
Non-contextual inequalities and dimensionality Johan Ahrens
... experiment and the assumptions made you may need to make sure that you can eject single particles from the source. Say we want to make an ’optical Stern-Gerlach’ experiment, this will work well since the photon, even though it is a spin-one particle, only assume the spin states -1 and 11 . The spin ...
... experiment and the assumptions made you may need to make sure that you can eject single particles from the source. Say we want to make an ’optical Stern-Gerlach’ experiment, this will work well since the photon, even though it is a spin-one particle, only assume the spin states -1 and 11 . The spin ...
Einstein-Podolsky-Rosen-Bohm laboratory
... |Φ. For instance, if in a laboratory EPRB experiment we find that E1 (a, b) shows a dependence on b that exceeds five times the standard deviation, this dependence cannot be attributed to |Φ deviating from the singlet state. Figure 2(left) shows the typical results of the Bell function S as a func ...
... |Φ. For instance, if in a laboratory EPRB experiment we find that E1 (a, b) shows a dependence on b that exceeds five times the standard deviation, this dependence cannot be attributed to |Φ deviating from the singlet state. Figure 2(left) shows the typical results of the Bell function S as a func ...
Slide 1
... GHZ and Bell’s theorem In 1935, after failing for years to defeat the uncertainty principle, Einstein argued that quantum mechanics is incomplete. Note that [x, ˆp] ≠ 0, but [x2–x1, pˆ 2+pˆ 1] = [x2, pˆ 2] – [x1, pˆ1] = 0. That means we can measure the distance between two particles and their total ...
... GHZ and Bell’s theorem In 1935, after failing for years to defeat the uncertainty principle, Einstein argued that quantum mechanics is incomplete. Note that [x, ˆp] ≠ 0, but [x2–x1, pˆ 2+pˆ 1] = [x2, pˆ 2] – [x1, pˆ1] = 0. That means we can measure the distance between two particles and their total ...
Physics of Single-Electron Transistors and Doped Mott Insulators M. Kastner
... from quantum fluctuations, and also a pseudodipolar interaction. Some of these small interactions also come into play in other lamellar cuprates, connected with the high-Tc superconductivity materials, and in many spin-chain and spin-ladder compounds. The classical ground state of this system is deg ...
... from quantum fluctuations, and also a pseudodipolar interaction. Some of these small interactions also come into play in other lamellar cuprates, connected with the high-Tc superconductivity materials, and in many spin-chain and spin-ladder compounds. The classical ground state of this system is deg ...
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.