Nonclassical states of light propagating in Kerr media
... the black-body radiation by introducing discrete packets of energy, which we now call photons. It was the beginning of quantum era. Nowadays, nonclassical properties of optical fields are the subject of intense studies for more than a decade now. Phenomena such as photon antibunching and squeezing, ...
... the black-body radiation by introducing discrete packets of energy, which we now call photons. It was the beginning of quantum era. Nowadays, nonclassical properties of optical fields are the subject of intense studies for more than a decade now. Phenomena such as photon antibunching and squeezing, ...
Chem-130 Test Lecture
... Heisenberg Uncertainty Principle: Werner Heisenberg proposed the uncertainty principle, which states that it is ...
... Heisenberg Uncertainty Principle: Werner Heisenberg proposed the uncertainty principle, which states that it is ...
Lecture 7
... There are t values of i with xi=1 t is now unknown We use smaller and smaller estimates for t and run the previous algorithm s=N/2,N/4,N/8,...,¼ t/2,... Every time we make O((N/s)1/2) queries Total number of queries s=N/2,N/4,...,t/2 (N/s)1/2 = O((N/t)1/2) Consider (N/t)-1/2 ¢ a=1,...,log N-log t+ ...
... There are t values of i with xi=1 t is now unknown We use smaller and smaller estimates for t and run the previous algorithm s=N/2,N/4,N/8,...,¼ t/2,... Every time we make O((N/s)1/2) queries Total number of queries s=N/2,N/4,...,t/2 (N/s)1/2 = O((N/t)1/2) Consider (N/t)-1/2 ¢ a=1,...,log N-log t+ ...
Quantum description of Einstein`s Brownian motion
... solubility given a certain phenomenological ansatz 关5兴, or on an axiomatic approach relying on mathematical input 关6,7兴, or on the exploitation of semiclassical correspondence 关8兴, we will base our microscopic analysis on the two key features of Einstein’s Brownian motion: homogeneity of the backgro ...
... solubility given a certain phenomenological ansatz 关5兴, or on an axiomatic approach relying on mathematical input 关6,7兴, or on the exploitation of semiclassical correspondence 关8兴, we will base our microscopic analysis on the two key features of Einstein’s Brownian motion: homogeneity of the backgro ...
1. You are given one of two quantum states of a single qubit: either
... success. For outcome |vi we guess that the qubit was in state |0i; for outcome |v⊥ i we guess that the qubit was in state |ψi. Determine the optimal measurement basis given this procedure. You can take α and β to be real numbers, in which case the normalization |α|2 + |β |2 = 1 implies that you can ...
... success. For outcome |vi we guess that the qubit was in state |0i; for outcome |v⊥ i we guess that the qubit was in state |ψi. Determine the optimal measurement basis given this procedure. You can take α and β to be real numbers, in which case the normalization |α|2 + |β |2 = 1 implies that you can ...
Quantum nature of laser light
... interference between beams from two lasers has been observed [2]. This seems to support the idea that laser light has a well-defined, if unknown, phase and thus supports the coherent state interpretation. Mølmer [1, 3], however, has examined the interference between two beams from laser cavities tha ...
... interference between beams from two lasers has been observed [2]. This seems to support the idea that laser light has a well-defined, if unknown, phase and thus supports the coherent state interpretation. Mølmer [1, 3], however, has examined the interference between two beams from laser cavities tha ...
Matter-Wave Interferometer for Large Molecules
... observed when all three gratings were tilted by the same amount. This is because the calculated interferometer phase shift from gravitation is Dwg 苷 0.2 rad per mrad of tilt (see below) and only its nonuniformity due to the finite velocity distribution diminishes the visibility. Longitudinal displac ...
... observed when all three gratings were tilted by the same amount. This is because the calculated interferometer phase shift from gravitation is Dwg 苷 0.2 rad per mrad of tilt (see below) and only its nonuniformity due to the finite velocity distribution diminishes the visibility. Longitudinal displac ...
History of Quantum Mechanics or the Comedy of Errors1 Jean
... But what worried Einstein is that, after the measurement of the position, the wave function changes and collapses to a wave function concentrated at or around the point where the particle is found. But that means that the value of the wave function suddenly jumps to zero everywhere, except where th ...
... But what worried Einstein is that, after the measurement of the position, the wave function changes and collapses to a wave function concentrated at or around the point where the particle is found. But that means that the value of the wave function suddenly jumps to zero everywhere, except where th ...
Isolation of the Conceptual Ingredients of Quantum Theory by Toy
... ingredients can systematically be chosen to fully reproduce the mystery cake, and now by construction an accurate recipe is known. A toy theory is like a toy cake. It does not attempt to make statements about reality that might stand up to testing: any desirable qualities like this are purely coinci ...
... ingredients can systematically be chosen to fully reproduce the mystery cake, and now by construction an accurate recipe is known. A toy theory is like a toy cake. It does not attempt to make statements about reality that might stand up to testing: any desirable qualities like this are purely coinci ...
Classical calculation of radiative lifetimes of atomic hydrogen in a
... as well as allowing for only discrete values of C for each value of n and m. Figure 1 shows the classical lifetime estimates obtained by both Eq. 共17兲 共solid black line兲 and the more approximate Eq. 共19兲 共dashed black line兲 for E = −R / 202 and for quantum-mechanically allowed values of Lz. Note tha ...
... as well as allowing for only discrete values of C for each value of n and m. Figure 1 shows the classical lifetime estimates obtained by both Eq. 共17兲 共solid black line兲 and the more approximate Eq. 共19兲 共dashed black line兲 for E = −R / 202 and for quantum-mechanically allowed values of Lz. Note tha ...
Optical gain in silicon nanocrystals
... obtained the gain spectrum for both samples A and B (Fig. 3; see also Supplementary Information). A wide spectral band is observed which spectrally overlaps the wavelength range of the luminescence, demonstrating that ampli®cation is produced by the radiative state associated with the nanocrystal±ox ...
... obtained the gain spectrum for both samples A and B (Fig. 3; see also Supplementary Information). A wide spectral band is observed which spectrally overlaps the wavelength range of the luminescence, demonstrating that ampli®cation is produced by the radiative state associated with the nanocrystal±ox ...
The Copenhagen Interpretation
... multiplied by its complex conjugate to give the predicted transition probability. In a more sophisticated calculation one might use density matrices pA(x';x") and PB(y'',y") instead of *A(J;) and ¥s(y) to represent the prepared system and the possible result. This would allow for preparations and me ...
... multiplied by its complex conjugate to give the predicted transition probability. In a more sophisticated calculation one might use density matrices pA(x';x") and PB(y'',y") instead of *A(J;) and ¥s(y) to represent the prepared system and the possible result. This would allow for preparations and me ...
Macroscopic Quantum Effects in Biophysics and
... macroscopic phenomena as well, usually treated by the methods of classical physics. In the history of quantum physics, and especially quantum mechanics, this question has been temporarily put aside for very different reasons, being considered as a difficult scientific problem. The situation is addit ...
... macroscopic phenomena as well, usually treated by the methods of classical physics. In the history of quantum physics, and especially quantum mechanics, this question has been temporarily put aside for very different reasons, being considered as a difficult scientific problem. The situation is addit ...
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.