Si based single electron transistor (SET) is fabricated successfully on p type SIMOX substrate,based on electron beam (EB) lithography,reactive ion etching (RIE) and thermal oxidation.In particular,using thermal oxi...Si based single electron transistor (SET) is fabricated successfully on p type SIMOX substrate,based on electron beam (EB) lithography,reactive ion etching (RIE) and thermal oxidation.In particular,using thermal oxidation and etching off the oxide layer,a one dimensional Si quantum wire can be converted into several quantum dots inside quantum wire in connection with the source and drain regions.The differential conductance (d I ds /d V ds ) oscillations and the Coulomb staircases in the source drain current ( I ds ) are shown clearly dependent on the source drain voltage at 5 3K.The I ds V gs (gate voltage) oscillations are observed from the I ds V gs characteristics as a function of V gs at different temperatures and various values of V ds .For a SET whose total capacitance is about 9 16aF,the I ds V gs oscillations can be observed at 77K.展开更多
In this paper we propose two quantum secure direct communication (QSDC) protocols with authentication.The authentication key expansion method is introduced to improve the life of the keys with security.In the first sc...In this paper we propose two quantum secure direct communication (QSDC) protocols with authentication.The authentication key expansion method is introduced to improve the life of the keys with security.In the first scheme,the third party, called Trent is introduced to authenticate the users that participate in the communication.He sends thepolarized photons in blocks to authenticate communication parties Alice and Bob using the authentication keys.In thecommunication process, polarized single photons are used to serve as the carriers, which transmit the secret messagesdirectly.The second QSDC process with authentication between two parties is also discussed.展开更多
Based on the commercially available avalanche photodiodes, the basic needs of gated-mode operation for single photon are discussed. Gated-mode technique based on the experimental data for detection of single photon is...Based on the commercially available avalanche photodiodes, the basic needs of gated-mode operation for single photon are discussed. Gated-mode technique based on the experimental data for detection of single photon is analyzed at communication wavelengths so that the basic operation parameters can decide properly for efficient detection of single photon. The bias voltage has related to the punch-through voltage in combining the cooling technique with synchronization to decrease the dark counts.展开更多
An alternative scheme is proposed to transfer quantum states and prepare a quantum network in cavity QED. It is based on the interaction of a two-mode cavity field with a three-level V-type atom. In the scheme, the at...An alternative scheme is proposed to transfer quantum states and prepare a quantum network in cavity QED. It is based on the interaction of a two-mode cavity field with a three-level V-type atom. In the scheme, the atom-cavity field interaction is resonant, thus the time required to complete the quantum state transfer process is greatly shortened, which is very important in view of decoherence. Moreover, the present scheme does not require one mode of the cavities to be initially prepared in one-photon state, thus it is more experimentally feasible than the previous ones.展开更多
We study the scattering process of photons confined in a one-dimensional optical waveguide by a laser controlled atomic ensemble. The investigation leads to an alternative setup of quantum node controlling the coheren...We study the scattering process of photons confined in a one-dimensional optical waveguide by a laser controlled atomic ensemble. The investigation leads to an alternative setup of quantum node controlling the coherent transfer of single photon in such one dimensional continuum. To exactly solve the effective scattering equations by using the discrete coordinate approach, we simulate the linear waveguide as a coupled resonator array at the high energy limit. We generally calculate the transmission eoet^cients and its vanishing at resonance reflects the good controllability of our scheme. We also show that there exist two bound states to describe the localize photons around the cavity.展开更多
By employing the dielectric continuum model and Loudon＇s uniaxial crystal model, the interface optical （IO） phonon modes in a freestanding quasi-one-dimensional （Q1D） wurtzite rectangular quantum wire are derived...By employing the dielectric continuum model and Loudon＇s uniaxial crystal model, the interface optical （IO） phonon modes in a freestanding quasi-one-dimensional （Q1D） wurtzite rectangular quantum wire are derived and analyzed. Numerical calculation on a freestanding wurtzite GaN quantum wire is performed. The resulte reveal that the dispersion frequencies of IO modes sensitively depend on the geometric structures of the Q1D wurtzite rectangular quantum wires, the free wave-number kz in z-direction and the dielectric constant of the nonpolar matrix. The degenerating behavior of the IO modes in Q1D wurtzite rectangular quantum wire has been clearly observed in the case of small wave-number kz and Iarge ratio of length to width of the rectangular crossing profile. The limited frequency behaviors of IO modes have been analyzed deeply, and detailed comparisons with those in wurtzite planar quantum wells and cylindrical quantum wires are also done. The present theories can be looked on as a generalization of that in isotropic rectangular quantum wires, and it can naturally reduce to the case of Q1D isotropic quantum wires once the anisotropy of the wurtzite material is ignored.展开更多
A single-photon detector is an extremely sensitive device capable of registering photons,offering essential technical support for optics quantum information applications.We review herein our recent experimental progre...A single-photon detector is an extremely sensitive device capable of registering photons,offering essential technical support for optics quantum information applications.We review herein our recent experimental progress in the development and application of single-photon detection techniques.Techniques based on advanced self-differencing,low-pass filtering,frequency up-conversion and photon-number-resolving are introduced for attaining high-speed,high-efficiency,low-noise single-photon detection at infrared wavelengths.The advantages of high-speed single-photon detection are discussed in some applications,such as the laser ranging and quantum key distribution.The photon-number-resolving detection is shown to support efficient quantum random number generation.展开更多
With the rapid development of microwave photonics technology, high-speed processing and ultra-weak signal detection capability have become the main bottlenecks in many applications. Thanks to the ultraweak signal dete...With the rapid development of microwave photonics technology, high-speed processing and ultra-weak signal detection capability have become the main bottlenecks in many applications. Thanks to the ultraweak signal detection capability and the extremely low timing jitter properties of single-photon detectors, the combination of single-photon detection and classical microwave photonics technology may provide a solution to break the above bottlenecks. In this paper, we first report a novel concept of singlephoton microwave photonics(SP-MWP), a SP-MWP signal processing system with phase shifting and frequency filtering functionalities is demonstrated based on a superconducting nanowire single photon detector(SNSPD) and a successive time-correlated single photon counting(TCSPC) module.Experimental results show that an ultrahigh optical sensitivity down to-100 d Bm has been achieved,and the signal processing bandwidth is only limited by the timing jitter of single-photon detectors. In the meantime, the proposed system demonstrates an ultrahigh anti-interference capability, only the signal which is phase locked by the trigger signal in TCSPC can be extracted from the detected signals combining with noise and strong interference. The proposed SP-MWP concept paves a way to a novel interdisciplinary field of microwave photonics and quantum mechanism, named by quantum microwave photonics.展开更多
Exploiting the optical excitation selection rules in graphene quantum dots, we investigate theoretically the entanglement generation process and entanglement concentration process of valley qubits. Our protocol shows ...Exploiting the optical excitation selection rules in graphene quantum dots, we investigate theoretically the entanglement generation process and entanglement concentration process of valley qubits. Our protocol shows that the graphene-based quantum dots can be distributed in a maximally entangled state through the interaction with single photons. In our proposed scheme, the setups are simplified as only single-photon detection is required. This provides a fast, all-optical manipulation of on-chip qubits,which gives an effective way for quantum information processing in graphene-based solid qubits.展开更多
A novel deterministic secure quantum communication （DSQC） scheme is presented based on Einstein- Podolsky-Rosen （EPR） pairs and single photons in this study. In this scheme, the secret message can be encoded direc...A novel deterministic secure quantum communication （DSQC） scheme is presented based on Einstein- Podolsky-Rosen （EPR） pairs and single photons in this study. In this scheme, the secret message can be encoded directly on the first particles of the prepared Bell states by simple unitary operations and decoded by performing the Bell-basis measurement after the additional classic information is exchanged. In addition, the strategy with two-step transmission of quantum data blocks and the technique of decoy-particle checking both are exploited to guarantee the security of the communication. Compared with some previous DSQC schemes, this scheme not oniy has a higher resource capacity, intrinsic efficiency and total efficiency, but also is more realizable in practical applications. Security anaJysis shows that the proposed scheme is unconditionally secure against various attacks over an ideal quantum channel and still conditionally robust over a noisy and lossy quantum channel.展开更多
Monolayer FeSe films grown on SrTiO_3(STO)substrate show superconducting gap-opening temperatures(T_c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based...Monolayer FeSe films grown on SrTiO_3(STO)substrate show superconducting gap-opening temperatures(T_c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based superconductors. Angle-resolved photoemission spectroscopy observed ‘‘replica bands' ' suggesting the importance of the interaction between FeSe electrons and STO phonons. These facts rejuvenated the quest for T_c enhancement mechanisms in iron-based, especially ironchalcogenide, superconductors. Here, we perform the first numerically-exact sign-problem-free quantum Monte Carlo simulations to iron-based superconductors. We(1) study the electronic pairing mechanism intrinsic to heavily electron doped FeSe films, and(2) examine the effects of electron–phonon interaction between FeSe and STO as well as nematic fluctuations on T_c. Armed with these results, we return to the question ‘‘what makes the Tcof monolayer FeSe on SrTiO_3 so high?'' in the conclusion and discussions.展开更多
Multipartite entangled states like the W-class are of growing interest since they exhibit a variety of possible applications ranging from quantum computation to genuine random number generation. Here, we present a uni...Multipartite entangled states like the W-class are of growing interest since they exhibit a variety of possible applications ranging from quantum computation to genuine random number generation. Here, we present a universal setup to generate high-order single photon W-states based on three-dimensional integrated-photonic waveguide struc- tures. Additionally, we present a novel method to charac- terize the device＇s unitary by means of classical light only.展开更多
In this paper, we propose a single-photon router via the use of a four-level atom system coupled with two one-dimensional coupled-resonator waveguides. A single photon can be directed from one quantum channel into ano...In this paper, we propose a single-photon router via the use of a four-level atom system coupled with two one-dimensional coupled-resonator waveguides. A single photon can be directed from one quantum channel into another by atomic spontaneous emission. The coherent resonance and the photonic bound states lead to the perfect reflection appearing in the incident channel.The fidelity of the atom is related to the magnitude of the coupling strength and can reach unit when the coupling strength matches g_a = g_b. This shows that the transfer of a single photon into another quantum channel has no influence on the fidelity at special points.展开更多
Research of superconducting nanowire singlephoton detectors(SNSPDs) has been progressing rapidly in recent years. The combined properties of high efficiency,low noise, and fast speed of SNSPDs permit its applications ...Research of superconducting nanowire singlephoton detectors(SNSPDs) has been progressing rapidly in recent years. The combined properties of high efficiency,low noise, and fast speed of SNSPDs permit its applications ranging from long-distance quantum teleportation to moonto-earth optical communications. Here we briefly discussed recent progress of SNSPDs, in particular(1) tungstensilicide SNSPDs,(2) waveguide-integrated SNSPDs, and(3) a few applied demonstrations.展开更多
文摘Si based single electron transistor (SET) is fabricated successfully on p type SIMOX substrate,based on electron beam (EB) lithography,reactive ion etching (RIE) and thermal oxidation.In particular,using thermal oxidation and etching off the oxide layer,a one dimensional Si quantum wire can be converted into several quantum dots inside quantum wire in connection with the source and drain regions.The differential conductance (d I ds /d V ds ) oscillations and the Coulomb staircases in the source drain current ( I ds ) are shown clearly dependent on the source drain voltage at 5 3K.The I ds V gs (gate voltage) oscillations are observed from the I ds V gs characteristics as a function of V gs at different temperatures and various values of V ds .For a SET whose total capacitance is about 9 16aF,the I ds V gs oscillations can be observed at 77K.
基金Supported by the National Fundamental Research Program under Grant No.2010CB923202Specialized Research Fund for the Doctoral Program of Education Ministry of China under Grant No.20090005120008+1 种基金 the Fundamental Research Funds for the Central Universities under Grant No.BUPT2009RC0710 China National Natural Science Foundation under Grant Nos.60871082,60937003 and 10947151
文摘In this paper we propose two quantum secure direct communication (QSDC) protocols with authentication.The authentication key expansion method is introduced to improve the life of the keys with security.In the first scheme,the third party, called Trent is introduced to authenticate the users that participate in the communication.He sends thepolarized photons in blocks to authenticate communication parties Alice and Bob using the authentication keys.In thecommunication process, polarized single photons are used to serve as the carriers, which transmit the secret messagesdirectly.The second QSDC process with authentication between two parties is also discussed.
基金National"973"Project(G2001039302) Key S & T Project of Guangdong Province(2003A103405) Key S&T Project of Guangzhou City(1992-2-035-01)
文摘Based on the commercially available avalanche photodiodes, the basic needs of gated-mode operation for single photon are discussed. Gated-mode technique based on the experimental data for detection of single photon is analyzed at communication wavelengths so that the basic operation parameters can decide properly for efficient detection of single photon. The bias voltage has related to the punch-through voltage in combining the cooling technique with synchronization to decrease the dark counts.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10225421 and 10674025
文摘An alternative scheme is proposed to transfer quantum states and prepare a quantum network in cavity QED. It is based on the interaction of a two-mode cavity field with a three-level V-type atom. In the scheme, the atom-cavity field interaction is resonant, thus the time required to complete the quantum state transfer process is greatly shortened, which is very important in view of decoherence. Moreover, the present scheme does not require one mode of the cavities to be initially prepared in one-photon state, thus it is more experimentally feasible than the previous ones.
基金Supported by the Natural Science Foundation of China under Grant Nos.10775048,10704023,10775048,and 10325523the National Fundamental Research Program of China under Grant No.2007CB925204the Scientific Research Fund of Hunan Provincial Education Department of China under Grant No.07C579
文摘We study the scattering process of photons confined in a one-dimensional optical waveguide by a laser controlled atomic ensemble. The investigation leads to an alternative setup of quantum node controlling the coherent transfer of single photon in such one dimensional continuum. To exactly solve the effective scattering equations by using the discrete coordinate approach, we simulate the linear waveguide as a coupled resonator array at the high energy limit. We generally calculate the transmission eoet^cients and its vanishing at resonance reflects the good controllability of our scheme. We also show that there exist two bound states to describe the localize photons around the cavity.
基金The project supported by the Science and Technology Project of Advanced Academy of Guangzhou City under Grant No. 2060. The author acknowledges the detailed and valuable discussions with Prof. J.J. Shi.
文摘By employing the dielectric continuum model and Loudon＇s uniaxial crystal model, the interface optical （IO） phonon modes in a freestanding quasi-one-dimensional （Q1D） wurtzite rectangular quantum wire are derived and analyzed. Numerical calculation on a freestanding wurtzite GaN quantum wire is performed. The resulte reveal that the dispersion frequencies of IO modes sensitively depend on the geometric structures of the Q1D wurtzite rectangular quantum wires, the free wave-number kz in z-direction and the dielectric constant of the nonpolar matrix. The degenerating behavior of the IO modes in Q1D wurtzite rectangular quantum wire has been clearly observed in the case of small wave-number kz and Iarge ratio of length to width of the rectangular crossing profile. The limited frequency behaviors of IO modes have been analyzed deeply, and detailed comparisons with those in wurtzite planar quantum wells and cylindrical quantum wires are also done. The present theories can be looked on as a generalization of that in isotropic rectangular quantum wires, and it can naturally reduce to the case of Q1D isotropic quantum wires once the anisotropy of the wurtzite material is ignored.
基金supported by the National Natural Science Fundation of China(Grant No.61127014)the National Key Scientific Instrument Project(Grant No.2012YQ150092)
文摘A single-photon detector is an extremely sensitive device capable of registering photons,offering essential technical support for optics quantum information applications.We review herein our recent experimental progress in the development and application of single-photon detection techniques.Techniques based on advanced self-differencing,low-pass filtering,frequency up-conversion and photon-number-resolving are introduced for attaining high-speed,high-efficiency,low-noise single-photon detection at infrared wavelengths.The advantages of high-speed single-photon detection are discussed in some applications,such as the laser ranging and quantum key distribution.The photon-number-resolving detection is shown to support efficient quantum random number generation.
基金supported by the National Key Research and Development Program of China (2018YFB2201902, 2018YFB2201901, and 2018YFB2201903)partly supported by the National Natural Science Foundation of China (61925505, 61535012, 61705217, 12033007, 61875205, 61801458, and 91836301)+1 种基金Frontier Science Key Research Project of CAS (QYZDB-SSW-SLH007)Strategic Priority Research Program of CAS (XDC07020200)
文摘With the rapid development of microwave photonics technology, high-speed processing and ultra-weak signal detection capability have become the main bottlenecks in many applications. Thanks to the ultraweak signal detection capability and the extremely low timing jitter properties of single-photon detectors, the combination of single-photon detection and classical microwave photonics technology may provide a solution to break the above bottlenecks. In this paper, we first report a novel concept of singlephoton microwave photonics(SP-MWP), a SP-MWP signal processing system with phase shifting and frequency filtering functionalities is demonstrated based on a superconducting nanowire single photon detector(SNSPD) and a successive time-correlated single photon counting(TCSPC) module.Experimental results show that an ultrahigh optical sensitivity down to-100 d Bm has been achieved,and the signal processing bandwidth is only limited by the timing jitter of single-photon detectors. In the meantime, the proposed system demonstrates an ultrahigh anti-interference capability, only the signal which is phase locked by the trigger signal in TCSPC can be extracted from the detected signals combining with noise and strong interference. The proposed SP-MWP concept paves a way to a novel interdisciplinary field of microwave photonics and quantum mechanism, named by quantum microwave photonics.
基金supported by the National Natural Science Foundation of China(1140403161205117+3 种基金and61471050)Beijing Higher Education Young Elite Teacher Project(YETP0456)the Fundamental Research Funds for the Central Universities(2014RC0903)the State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications)
文摘Exploiting the optical excitation selection rules in graphene quantum dots, we investigate theoretically the entanglement generation process and entanglement concentration process of valley qubits. Our protocol shows that the graphene-based quantum dots can be distributed in a maximally entangled state through the interaction with single photons. In our proposed scheme, the setups are simplified as only single-photon detection is required. This provides a fast, all-optical manipulation of on-chip qubits,which gives an effective way for quantum information processing in graphene-based solid qubits.
基金Supported by the National Natural Science Foundation of China under Grant No.61272501the National Key Basic Research Program(NKBRP)(973 program)(2012CB315905)the Beijing Natural Science Foundation under Grant No.4132056
文摘A novel deterministic secure quantum communication （DSQC） scheme is presented based on Einstein- Podolsky-Rosen （EPR） pairs and single photons in this study. In this scheme, the secret message can be encoded directly on the first particles of the prepared Bell states by simple unitary operations and decoded by performing the Bell-basis measurement after the additional classic information is exchanged. In addition, the strategy with two-step transmission of quantum data blocks and the technique of decoy-particle checking both are exploited to guarantee the security of the communication. Compared with some previous DSQC schemes, this scheme not oniy has a higher resource capacity, intrinsic efficiency and total efficiency, but also is more realizable in practical applications. Security anaJysis shows that the proposed scheme is unconditionally secure against various attacks over an ideal quantum channel and still conditionally robust over a noisy and lossy quantum channel.
基金the National Supercomputer Center in Guangzhou for computational supportZXL and HY were supported in part by the National Thousand Young-Talents Program and the National Natural Science Foundation of China (11474175)+1 种基金FW was supported by the National Natural Science Foundation of China (11374018)DHL was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, Grant DE-AC0205CH11231
文摘Monolayer FeSe films grown on SrTiO_3(STO)substrate show superconducting gap-opening temperatures(T_c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based superconductors. Angle-resolved photoemission spectroscopy observed ‘‘replica bands' ' suggesting the importance of the interaction between FeSe electrons and STO phonons. These facts rejuvenated the quest for T_c enhancement mechanisms in iron-based, especially ironchalcogenide, superconductors. Here, we perform the first numerically-exact sign-problem-free quantum Monte Carlo simulations to iron-based superconductors. We(1) study the electronic pairing mechanism intrinsic to heavily electron doped FeSe films, and(2) examine the effects of electron–phonon interaction between FeSe and STO as well as nematic fluctuations on T_c. Armed with these results, we return to the question ‘‘what makes the Tcof monolayer FeSe on SrTiO_3 so high?'' in the conclusion and discussions.
基金financial support from the German Ministry of Education and Research (Center for Innovation Competence program, Grant No. 03Z1HN31)the Thuringian Ministry for Education, Science and Culture (Research group Spacetime, Grant No. 11027-514)+1 种基金the Deutsche Forschungsgemeinschaft (Grant No. NO462/6-1)the German-Israeli Foundation for Scientific Research and Development (Grant No. 1157-127.14/ 2011)
文摘Multipartite entangled states like the W-class are of growing interest since they exhibit a variety of possible applications ranging from quantum computation to genuine random number generation. Here, we present a universal setup to generate high-order single photon W-states based on three-dimensional integrated-photonic waveguide struc- tures. Additionally, we present a novel method to charac- terize the device＇s unitary by means of classical light only.
基金supported by the National Natural Science Foundation of China(Grant Nos.11674253,61471356,and 11365009)
文摘In this paper, we propose a single-photon router via the use of a four-level atom system coupled with two one-dimensional coupled-resonator waveguides. A single photon can be directed from one quantum channel into another by atomic spontaneous emission. The coherent resonance and the photonic bound states lead to the perfect reflection appearing in the incident channel.The fidelity of the atom is related to the magnitude of the coupling strength and can reach unit when the coupling strength matches g_a = g_b. This shows that the transfer of a single photon into another quantum channel has no influence on the fidelity at special points.
基金supported by the National Natural Science Foundation of China(61505141 and 11527808)the National Thousand Talents Plan for Young Professionals
文摘Research of superconducting nanowire singlephoton detectors(SNSPDs) has been progressing rapidly in recent years. The combined properties of high efficiency,low noise, and fast speed of SNSPDs permit its applications ranging from long-distance quantum teleportation to moonto-earth optical communications. Here we briefly discussed recent progress of SNSPDs, in particular(1) tungstensilicide SNSPDs,(2) waveguide-integrated SNSPDs, and(3) a few applied demonstrations.
