Aiming at the problems existing in the teaching reform of mechanical foundation course,such as old teaching mode,poor practical teaching means and lack of innovative thinking training.In order to realize the reform of...Aiming at the problems existing in the teaching reform of mechanical foundation course,such as old teaching mode,poor practical teaching means and lack of innovative thinking training.In order to realize the reform of teaching contents and methods and effectively promote the improvement of students’ability,it is necessary to improve teaching contents,innovate teaching methods and strengthen the design of practical teaching links and innovative thinking ability cultivation schemes.展开更多
Quantum phase measurement with multiphoton twin-Fock states has been shown to be optimal for detecting equal numbers of photons at the output ports of a Mach–Zehnder interferometer(i.e., the so-called single-fringe d...Quantum phase measurement with multiphoton twin-Fock states has been shown to be optimal for detecting equal numbers of photons at the output ports of a Mach–Zehnder interferometer(i.e., the so-called single-fringe detection), since the phase sensitivity can saturate the quantum Cramér–Rao lower bound at certain values of phase shift. Here we report a further step to achieve a global phase estimation at the Heisenberg limit by detecting the particle-number difference(i.e., the ?_z measurement). We show the role of experimental imperfections on the ultimate estimation precision with the six-photon twin-Fock state of light. Our results show that both the precision and the sensing region of the ?_z measurement are better than those of the single-fringe detection, due to combined contributions of the measurement outcomes. We numerically simulate the phase estimation protocol using an asymptotically unbiased maximum likelihood estimator.展开更多
Euler angles and Euler kinematics equation of terminal sensing ammunition are expressed and rewritten by using quaternion to solve the singular problem in using Euler angles to describe the motion.The contrastive simu...Euler angles and Euler kinematics equation of terminal sensing ammunition are expressed and rewritten by using quaternion to solve the singular problem in using Euler angles to describe the motion.The contrastive simulations are performed in order to validate the correctness and advantage of the quaternion description.The simulation results show that the dynamic model with quaternion have stable solution,there is not singular point in the calculation,and the ballistic model rewritten by using the quaternion is suitable for describing the terminal sensing ammunition's scanning motion than the common Euler equation.展开更多
Counterfactual definiteness must be used as at least one of the postulates or axioms that are necessary to derive Bell-type inequalities. It is considered by many to be a postulate that not only is commensurate with c...Counterfactual definiteness must be used as at least one of the postulates or axioms that are necessary to derive Bell-type inequalities. It is considered by many to be a postulate that not only is commensurate with classical physics (as for example Einstein’s special relativity), but also separates and distinguishes classical physics from quantum mechanics. It is the purpose of this paper to show that Bell’s choice of mathematical functions and independent variables implicitly includes counterfactual definiteness. However, his particular choice of variables reduces the generality of his theory, as well as the physics of all Bell-type theories, so significantly that no meaningful comparison of these theories with actual Einstein-Podolsky-Rosen experiments can be made.展开更多
Bohr’s principle of complementarity has a long history and it is an important topic in quantum theory,among which the famous example is the duality relation.The relation between visibilityC and distinguishability D,C...Bohr’s principle of complementarity has a long history and it is an important topic in quantum theory,among which the famous example is the duality relation.The relation between visibilityC and distinguishability D,C2+D2≤1,has long been recognized as the only representative of the duality relation.However,recent researches have shown that this inequality is not good enough because it is not tight for multipath interferometers.Meanwhile,a tight bound for the multipath interferometer has been put forward.Here we design and experimentally implement a three-path interferometer coupling with path indicator states.The wave property of photons is characterized by l1-norm coherence measure,and the particle property is based on distinguishability of the indicator states.The new duality relation of the three-path interferometer is demonstrated in our experiment,which bounds the union of a right triangle and a part of elliptical area inside the quadrant of a unit circle.Data analysis confirms that the new bound is tight for photons in three-path interferometers.展开更多
The description of the microscopic world in quantum mechanics is very different from that in classical physics, and there are some points of view that are contrary to intuition and logic. The first is the problem of r...The description of the microscopic world in quantum mechanics is very different from that in classical physics, and there are some points of view that are contrary to intuition and logic. The first is the problem of reality;quantum mechanics believes the behavior of micro particles is random and jumping. The second is the loss of certainty;the conjugate physical variables of a system cannot be determined synchronously, they satisfy the Heisenberg uncertainty principle. The third is the non-local correlation. The measurement of one particle in the quantum entanglement pair will influence the state of the other entangled particle simultaneously. In this paper, some concepts related to quantum entanglement, such as EPR correlation, quantum entanglement correlation function, Bell’s inequality and so on, are analyzed in detail. Analysis shows that the mystery and confusion in quantum theory may be caused by the logical problems in its basic framework. Bell’s inequality is only a mathematical theorem, but its physical meaning is actually unclear. The Bell state of quantum entangled pair may not satisfy the dynamic equation of quantum theory, so it cannot describe the true state of microscopic particles. In this paper, the correct correlation functions of spin entanglement pair and photonic entanglement pair are strictly derived according to normal logic. Quantum theory is a more fundamental theory than classical mechanics, and they are not equal relation in logic. However, there are still some unreasonable contents in the framework of quantum theory, which need to be improved. In order to disclose the real relationship between quantum theory and classical mechanics, we propose some experiments which provide intuitionistic teaching materials for the new interpretation of quantum theory.展开更多
Effects of a Bohmian type quantum-relativistic theory are explored.The model is obtained by introducing a new and independent time parameter whose relative motions are not directly observable and cause quantum uncerta...Effects of a Bohmian type quantum-relativistic theory are explored.The model is obtained by introducing a new and independent time parameter whose relative motions are not directly observable and cause quantum uncertainties of the physical observables.Unlike the usual de Broglie-Bohm theories,the Quantum Potential does not directly affect the observable motion,but determines the one that is relative to the new time variable.It turns out that the Zitterbewegung of a free particle,of which a more general law is obtained,is the key example of these hidden motions and,through it,it seems possible to give physical reality to the Feynman's paths.A relativistic revision of the uncertainty principle is also derived from the theory.展开更多
文摘Aiming at the problems existing in the teaching reform of mechanical foundation course,such as old teaching mode,poor practical teaching means and lack of innovative thinking training.In order to realize the reform of teaching contents and methods and effectively promote the improvement of students’ability,it is necessary to improve teaching contents,innovate teaching methods and strengthen the design of practical teaching links and innovative thinking ability cultivation schemes.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91636108,11775190,and 11774024)Science Foundation of Zhejiang Sci-Tech University,China(Grant No.18062145-Y)+1 种基金Open Foundation of Key Laboratory of Optical Field Manipulation of Zhejiang Province,China(Grant No.ZJOFM-2019-002)Science Challenge Project,China(Grant No.TZ2018003)
文摘Quantum phase measurement with multiphoton twin-Fock states has been shown to be optimal for detecting equal numbers of photons at the output ports of a Mach–Zehnder interferometer(i.e., the so-called single-fringe detection), since the phase sensitivity can saturate the quantum Cramér–Rao lower bound at certain values of phase shift. Here we report a further step to achieve a global phase estimation at the Heisenberg limit by detecting the particle-number difference(i.e., the ?_z measurement). We show the role of experimental imperfections on the ultimate estimation precision with the six-photon twin-Fock state of light. Our results show that both the precision and the sensing region of the ?_z measurement are better than those of the single-fringe detection, due to combined contributions of the measurement outcomes. We numerically simulate the phase estimation protocol using an asymptotically unbiased maximum likelihood estimator.
文摘Euler angles and Euler kinematics equation of terminal sensing ammunition are expressed and rewritten by using quaternion to solve the singular problem in using Euler angles to describe the motion.The contrastive simulations are performed in order to validate the correctness and advantage of the quaternion description.The simulation results show that the dynamic model with quaternion have stable solution,there is not singular point in the calculation,and the ballistic model rewritten by using the quaternion is suitable for describing the terminal sensing ammunition's scanning motion than the common Euler equation.
文摘Counterfactual definiteness must be used as at least one of the postulates or axioms that are necessary to derive Bell-type inequalities. It is considered by many to be a postulate that not only is commensurate with classical physics (as for example Einstein’s special relativity), but also separates and distinguishes classical physics from quantum mechanics. It is the purpose of this paper to show that Bell’s choice of mathematical functions and independent variables implicitly includes counterfactual definiteness. However, his particular choice of variables reduces the generality of his theory, as well as the physics of all Bell-type theories, so significantly that no meaningful comparison of these theories with actual Einstein-Podolsky-Rosen experiments can be made.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0302700 and 2017YFA0304100)the National Natural Science Foundation of China(Grant Nos.11822408,11674304,11774335,61490711,11474267,11821404,11325419,11904356,and 91321313)+5 种基金the Youth Innovation Promotion Association,Chinese Academy of Sciences(Grant No.2017492)the Foundation for Scientific Instrument and Equipment Development,Chinese Academy of Sciences(Grant No.YJKYYQ20170032)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDY-SSW-SLH003),the Fundamental Research Funds for the Central Universities,China(Grant Nos.WK2470000026 and WK2030000008)Science Foundation of Chinese Academy of Sciences(Grant No.ZDRW-XH-2019-1),Anhui Initiative in Quantum Information Technologies,China(Grant Nos.AHY020100,AHYPT003,and AHY060300)the National Postdoctoral Program for Innovative Talents of China(Grant No.BX20180293)the China Postdoctoral Science Foundation(Grant No.2018M640587).
文摘Bohr’s principle of complementarity has a long history and it is an important topic in quantum theory,among which the famous example is the duality relation.The relation between visibilityC and distinguishability D,C2+D2≤1,has long been recognized as the only representative of the duality relation.However,recent researches have shown that this inequality is not good enough because it is not tight for multipath interferometers.Meanwhile,a tight bound for the multipath interferometer has been put forward.Here we design and experimentally implement a three-path interferometer coupling with path indicator states.The wave property of photons is characterized by l1-norm coherence measure,and the particle property is based on distinguishability of the indicator states.The new duality relation of the three-path interferometer is demonstrated in our experiment,which bounds the union of a right triangle and a part of elliptical area inside the quadrant of a unit circle.Data analysis confirms that the new bound is tight for photons in three-path interferometers.
文摘The description of the microscopic world in quantum mechanics is very different from that in classical physics, and there are some points of view that are contrary to intuition and logic. The first is the problem of reality;quantum mechanics believes the behavior of micro particles is random and jumping. The second is the loss of certainty;the conjugate physical variables of a system cannot be determined synchronously, they satisfy the Heisenberg uncertainty principle. The third is the non-local correlation. The measurement of one particle in the quantum entanglement pair will influence the state of the other entangled particle simultaneously. In this paper, some concepts related to quantum entanglement, such as EPR correlation, quantum entanglement correlation function, Bell’s inequality and so on, are analyzed in detail. Analysis shows that the mystery and confusion in quantum theory may be caused by the logical problems in its basic framework. Bell’s inequality is only a mathematical theorem, but its physical meaning is actually unclear. The Bell state of quantum entangled pair may not satisfy the dynamic equation of quantum theory, so it cannot describe the true state of microscopic particles. In this paper, the correct correlation functions of spin entanglement pair and photonic entanglement pair are strictly derived according to normal logic. Quantum theory is a more fundamental theory than classical mechanics, and they are not equal relation in logic. However, there are still some unreasonable contents in the framework of quantum theory, which need to be improved. In order to disclose the real relationship between quantum theory and classical mechanics, we propose some experiments which provide intuitionistic teaching materials for the new interpretation of quantum theory.
文摘Effects of a Bohmian type quantum-relativistic theory are explored.The model is obtained by introducing a new and independent time parameter whose relative motions are not directly observable and cause quantum uncertainties of the physical observables.Unlike the usual de Broglie-Bohm theories,the Quantum Potential does not directly affect the observable motion,but determines the one that is relative to the new time variable.It turns out that the Zitterbewegung of a free particle,of which a more general law is obtained,is the key example of these hidden motions and,through it,it seems possible to give physical reality to the Feynman's paths.A relativistic revision of the uncertainty principle is also derived from the theory.