1 Heisenberg Uncertainty Principle
... A question that has been studied ever since Heisenberg’s original paper is whether a precise inequality can be established for the case where actual measurements are made on a quantum system. As of October, 2013, this has not been definitively settled, but we can discuss the general framework present ...
... A question that has been studied ever since Heisenberg’s original paper is whether a precise inequality can be established for the case where actual measurements are made on a quantum system. As of October, 2013, this has not been definitively settled, but we can discuss the general framework present ...
Slide 1
... [running time] ~Kn (or even only with ~Kn2), this would have consequences of the greatest magnitude. —Gödel to von Neumann, 1956 ...
... [running time] ~Kn (or even only with ~Kn2), this would have consequences of the greatest magnitude. —Gödel to von Neumann, 1956 ...
2.5 The Schmidt decomposition and purifications
... This chapter has focused on introducing the tools and mathematics of quantum mechanics. As these techniques are applied in the following chapters of this book, an important recurring theme is the unusual, non-classical properties of quantum mechanics. But what exactly is the difference between quant ...
... This chapter has focused on introducing the tools and mathematics of quantum mechanics. As these techniques are applied in the following chapters of this book, an important recurring theme is the unusual, non-classical properties of quantum mechanics. But what exactly is the difference between quant ...
The nonlinearity of single photon
... used a cavity with a finesse of 63,000 and a cold cloud of caesium atoms at a temperature of 100 μK. Critical to the success of the experiment was achieving a high optical depth for the atomic ensemble. The researchers trapped around 105 atoms in an off-resonant optical lattice to give a single-pass ...
... used a cavity with a finesse of 63,000 and a cold cloud of caesium atoms at a temperature of 100 μK. Critical to the success of the experiment was achieving a high optical depth for the atomic ensemble. The researchers trapped around 105 atoms in an off-resonant optical lattice to give a single-pass ...
PDF
... Massachusetts Institute of Technology, Research Laboratory of Electronics, Cambridge, MA 02139, USA ...
... Massachusetts Institute of Technology, Research Laboratory of Electronics, Cambridge, MA 02139, USA ...
Chapter 7 -- Radiative Corrections: some formal developments Chapter 7:
... Hydrogen atoms in the state, which has a very long lifetime because of selection rules. Microwave radiation with a (fixed) frequency of 2395 MHz was used to cause transitions to the state and a magnetic field was adjusted to shift the energy of the states until the rate was largest. The decay of the ...
... Hydrogen atoms in the state, which has a very long lifetime because of selection rules. Microwave radiation with a (fixed) frequency of 2395 MHz was used to cause transitions to the state and a magnetic field was adjusted to shift the energy of the states until the rate was largest. The decay of the ...
Slide 1
... N. S. Yanofsky and M. A. Mannucci, Quantum Computing for Computer Scientists, 1 ed. New York, NY: Cambridge University Press, 2008. ...
... N. S. Yanofsky and M. A. Mannucci, Quantum Computing for Computer Scientists, 1 ed. New York, NY: Cambridge University Press, 2008. ...
Slide 1
... for which n = 2 are larger than those for which n = 1, for example. Because they have opposite electrical charges, electrons are attracted to the nucleus of the atom. Energy must therefore be absorbed to excite an electron from an orbital in which the electron is close to the nucleus (n = 1) into an ...
... for which n = 2 are larger than those for which n = 1, for example. Because they have opposite electrical charges, electrons are attracted to the nucleus of the atom. Energy must therefore be absorbed to excite an electron from an orbital in which the electron is close to the nucleus (n = 1) into an ...
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
... F. Plot the (time-independent) fractional modulation, It is common to talk about the time evolution as if the system is moving in state space (as opposed to coordinate space) back and forth between the Bright and Dark states. ...
... F. Plot the (time-independent) fractional modulation, It is common to talk about the time evolution as if the system is moving in state space (as opposed to coordinate space) back and forth between the Bright and Dark states. ...
RPA - Department of Theoretical Physics UMCS
... excited vibrational states of the negative signature that can be used to identify wobbling excitations and the sign of -deformation. ...
... excited vibrational states of the negative signature that can be used to identify wobbling excitations and the sign of -deformation. ...
On High-Efficiency Optical Communication and Key Distribution
... and degrade easily over poor atmospheric conditions. In Section III we propose to solve this problem using simple dense (thus non-orthogonal) Gaussian beams; by using spatial PPM modulation, interference between the beams is transformed into a simple noisy channel. We present the fundamental hardwar ...
... and degrade easily over poor atmospheric conditions. In Section III we propose to solve this problem using simple dense (thus non-orthogonal) Gaussian beams; by using spatial PPM modulation, interference between the beams is transformed into a simple noisy channel. We present the fundamental hardwar ...
On High-Efficiency Optical Communication and Key Distribution
... and degrade easily over poor atmospheric conditions. In Section III we propose to solve this problem using simple dense (thus non-orthogonal) Gaussian beams; by using spatial PPM modulation, interference between the beams is transformed into a simple noisy channel. We present the fundamental hardwar ...
... and degrade easily over poor atmospheric conditions. In Section III we propose to solve this problem using simple dense (thus non-orthogonal) Gaussian beams; by using spatial PPM modulation, interference between the beams is transformed into a simple noisy channel. We present the fundamental hardwar ...
authentication with quantum smart-card
... Moreover, if the eavesdropper makes no changes, the teller machine should always accept, and the fidelity should be exactly 1. Of course, this informal definition is impossible to attain. The eavesdropper might always replace QC smart-card 's transmitted message with a completely mixed state. There ...
... Moreover, if the eavesdropper makes no changes, the teller machine should always accept, and the fidelity should be exactly 1. Of course, this informal definition is impossible to attain. The eavesdropper might always replace QC smart-card 's transmitted message with a completely mixed state. There ...
Quantum Correlations with Spacelike Separated Beam Splitters in
... It is not sufficient to precisely equalize the path lengths, we also have to ensure that the coherence length of the photons is smaller than the permitted discrepancy. This is the case because, with the interference filter placed after the photon pair source, the photons coherence length is about 0. ...
... It is not sufficient to precisely equalize the path lengths, we also have to ensure that the coherence length of the photons is smaller than the permitted discrepancy. This is the case because, with the interference filter placed after the photon pair source, the photons coherence length is about 0. ...
The presentation template
... Alice makes one of four measurements and then sends her qubit to Bob ...
... Alice makes one of four measurements and then sends her qubit to Bob ...
AdiabaticQC - University of California, Berkeley
... from the initial to the final state. Let T be the final time, at the end of the process. Let t be the independent time variable. Define s = t/T such that during the evolution of the system, 0 < s < 1. Then the Hamiltonian is a function of s such that: ...
... from the initial to the final state. Let T be the final time, at the end of the process. Let t be the independent time variable. Define s = t/T such that during the evolution of the system, 0 < s < 1. Then the Hamiltonian is a function of s such that: ...
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.