Large quantum superpositions of a levitated nanodiamond through spin-optomechanical coupling
... objects is one of the most challenging and attractive goals in macroscopic quantum mechanics [1–4]. It provides potential opportunities to experimentally test different wave-function collapse models [2], including gravity-induced state reduction [5], which is a manifestation of the apparent conflict ...
... objects is one of the most challenging and attractive goals in macroscopic quantum mechanics [1–4]. It provides potential opportunities to experimentally test different wave-function collapse models [2], including gravity-induced state reduction [5], which is a manifestation of the apparent conflict ...
detail links - Shanghai Institute of Technical Physics
... nm. GaAs QDs are considered here. The effective masses of electrons and holes are m e = 0.067 and mh = 0.51, respectively, in the unit of electron rest mass, and the band gap is E g = 1.51914 eV [26]. The corresponding ground-state exciton resonance frequency ω 0 of QDs is then given as 1.535 eV [5] ...
... nm. GaAs QDs are considered here. The effective masses of electrons and holes are m e = 0.067 and mh = 0.51, respectively, in the unit of electron rest mass, and the band gap is E g = 1.51914 eV [26]. The corresponding ground-state exciton resonance frequency ω 0 of QDs is then given as 1.535 eV [5] ...
1996 Orchestrated Objective Reduction of Quantum Coherence in
... Schrödinger equation) denoted by U. Large-scale (classical) systems seem to obey (different) computable deterministic laws. The transition when system effects are magnified from the small, quantum scale to the large, classical scale (measurement process) chooses a particular "eigenstate"(one state o ...
... Schrödinger equation) denoted by U. Large-scale (classical) systems seem to obey (different) computable deterministic laws. The transition when system effects are magnified from the small, quantum scale to the large, classical scale (measurement process) chooses a particular "eigenstate"(one state o ...
Dynamics of Quantum Many Body Systems Far From Thermal
... different nonequilibrium regimes. Clearly the subject is extremely broad both in terms of nonequilibrium settings and model systems considered and we will have to make a selection. In the first part we will focus on the dynamics of thermally isolated systems after rapid change in time of some parame ...
... different nonequilibrium regimes. Clearly the subject is extremely broad both in terms of nonequilibrium settings and model systems considered and we will have to make a selection. In the first part we will focus on the dynamics of thermally isolated systems after rapid change in time of some parame ...
Seventh lecture, 18.11.03 (Tunneling times and introduction to weak
... spin about z) –– Note that this measurement is thus just another interference effect, as the precession angle f is the phase difference accumulated between and . • We want to know the outcome of this von Neumann measurement only for those cases where the particle is transmitted. • "Being transmit ...
... spin about z) –– Note that this measurement is thus just another interference effect, as the precession angle f is the phase difference accumulated between and . • We want to know the outcome of this von Neumann measurement only for those cases where the particle is transmitted. • "Being transmit ...
Coherent States
... Here I digress from work in progress—namely, a review of a paper by C. Y. She & H. Heffner1 , which was the first of several papers inspired by E. Arthurs & J. L. Kelly’s “On the simultaneous measurement of a pair of conjugate observables” (BSTJ 44, 725 (1965)); it is my intention to incorporate tha ...
... Here I digress from work in progress—namely, a review of a paper by C. Y. She & H. Heffner1 , which was the first of several papers inspired by E. Arthurs & J. L. Kelly’s “On the simultaneous measurement of a pair of conjugate observables” (BSTJ 44, 725 (1965)); it is my intention to incorporate tha ...
Classical vs Quantum Information - UMD Math
... for the single box) as: [(a1 ⊕ AL ) ⊕ A] ⊕ B2 Suppose Bob wants to predict a3 . This corresponds to b1 = 0, b2 = 1. He takes the Bob-output of the R box (which corresponds to the pair (a3 , a4 )) and adds this to the above bit: [(a1 ⊕ AL ) ⊕ A] ⊕ B1 ⊕ B2 This is his final response (his guess for the ...
... for the single box) as: [(a1 ⊕ AL ) ⊕ A] ⊕ B2 Suppose Bob wants to predict a3 . This corresponds to b1 = 0, b2 = 1. He takes the Bob-output of the R box (which corresponds to the pair (a3 , a4 )) and adds this to the above bit: [(a1 ⊕ AL ) ⊕ A] ⊕ B1 ⊕ B2 This is his final response (his guess for the ...
M. Shiga and W. Shinoda, heat capacity of water from quantum nuclear dynamics
... systems such as rare-gas clusters except for our preliminary study on water.22 As we will see later in the results of our simulation, the current status might be ascribed to the shortage of computer power and the lack of the efficient heatcapacity estimator until recently. If these difficulties were ...
... systems such as rare-gas clusters except for our preliminary study on water.22 As we will see later in the results of our simulation, the current status might be ascribed to the shortage of computer power and the lack of the efficient heatcapacity estimator until recently. If these difficulties were ...
Quantum Manipulation of Ultracold Atoms—V. Vuletic
... Laser cooling of atoms has not only enabled Bose-Einstein condensation, but has also resulted in a number of important applications and devices, many of which are tied to precision measurements and atomic clocks. However, laser cooling has so far been limited to atoms with a relatively simple intern ...
... Laser cooling of atoms has not only enabled Bose-Einstein condensation, but has also resulted in a number of important applications and devices, many of which are tied to precision measurements and atomic clocks. However, laser cooling has so far been limited to atoms with a relatively simple intern ...
Introduction to quantum statistical thermodynamics by Armen
... including a pure state |ψ⟩⟨ψ|, describes an ensemble of identically prepared systems. For instance, in an ideal SternGerlach experiment all particles of the upper beam together are described by the wavefunction | ↑⟩ or the pure density matix | ↑⟩⟨↑ |. The description is optimal, in the sense that al ...
... including a pure state |ψ⟩⟨ψ|, describes an ensemble of identically prepared systems. For instance, in an ideal SternGerlach experiment all particles of the upper beam together are described by the wavefunction | ↑⟩ or the pure density matix | ↑⟩⟨↑ |. The description is optimal, in the sense that al ...
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.