CN112951011B - Multifunctional optical quantum computer teaching system - Google Patents

Abstract

The present invention provides a multifunctional optical quantum computer teaching system, which comprises an optical quantum computer device and an optical quantum computing software operating system; wherein the optical quantum computing software operating system comprises an optical quantum computer device connection diagram, a controlled NOT gate manipulation interface, and a Deutsch‑Jozsa algorithm operation interface; the optical quantum computer device comprises a laser, a nonlinear crystal, a linear optical device, an optical quantum computing processor, and a quantum state measurement system; wherein the optical quantum computing processor and the quantum state measurement system are connected via the optical quantum computer device connection diagram; the optical quantum computing processor comprises a quantum light source, a single-bit quantum gate, and a controlled NOT gate.

Description

Multifunctional optical quantum computer teaching system

Technical Field

The present invention relates to the field of quantum information technology, and in particular to a multifunctional optical quantum computer teaching system, which is suitable for application fields such as quantum computing and teaching experiments.

Background Art

Quantum computers can utilize the superposition and entanglement of physical states, and can exponentially accelerate large number factorization and other problems compared to traditional computers. Since quantum computing was proposed in the 1980s, scientists from all over the world have conducted research in this direction. In recent years, not only in the field of scientific research, but also in various large technology companies, investment in quantum computing research has increased. In 2019 and 2020, scientists in the United States and China successively realized quantum simulators that surpassed the computing power of classical computers on superconducting quantum computer systems and optical quantum computer systems, which also made the competition in the research of quantum computers more intense.

At present, the development of quantum computing is still in its early stages. The research on quantum computing is mainly focused on superconducting, optical, ion trap and other systems. The equipment used in the research is expensive, the technical requirements of researchers are high, and there is a shortage of personnel. At the same time, the quantum computing courses in various universities are still in the theoretical learning stage, the quantum computing experimental teaching is immature, and there is a lack of corresponding professional equipment. In order to better carry out the teaching and talent training of quantum computing and attract more talents to conduct research on quantum computing, it is urgent to develop corresponding quantum computing teaching equipment.

Summary of the invention

In view of this, the main purpose of the present invention is to provide a multifunctional optical quantum computer teaching system, in order to partially solve at least one of the above-mentioned technical problems.

In order to achieve the above-mentioned object, as one aspect of the present invention, a multifunctional optical quantum computer teaching system is provided, wherein the teaching system comprises an optical quantum computer device and an optical quantum computing software operating system; wherein,

The optical quantum computing software operating system includes an optical quantum computer device connection diagram, a control NOT gate operation interface, and a Deutsch-Jozsa algorithm operation interface;

The optical quantum computer device includes a laser, a nonlinear crystal, a linear optical device, an optical quantum computing processor and a quantum state measurement system; wherein the optical quantum computing processor and the quantum state measurement system are connected via the optical quantum computer device connection diagram; the optical quantum computing processor includes a quantum light source, a single-bit quantum gate and a controlled NOT gate.

Optionally, the quantum light source includes a laser for generating initial pump light with a wavelength range of 300nm-450nm; the laser is a continuous laser or a pulsed laser with a half-width range of 0.01-10nm.

Optionally, the quantum light source further includes a focusing lens for focusing the pump light onto a nonlinear crystal to generate two-photon pairs; the nonlinear crystal includes a type 0 phase-matching crystal, a type I phase-matching crystal, and a type II phase-matching crystal.

Optionally, the quantum light source is a two-way triggered single-photon source.

Optionally, the optical quantum computing processor also includes a half-wave plate and a partial polarization beam splitter for rotating the polarization of photons and separating the paths.

Optionally, the controlled NOT gate is used to entangle two independent photons.

Optionally, the quantum state measurement system includes a half-wave plate, a quarter-wave plate, a polarization beam splitter and a single-photon detector, which are used to perform tomographic measurement of the polarization state of photons.

Optionally, the control NOT gate manipulation interface encodes the polarization states of two photons, measures the calculation results simultaneously, and finally outputs a logic truth table under different basis vectors.

Optionally, the control NOT gate manipulation interface encodes the polarization states of two photons, forms four maximum entangled states of two photons through the control NOT gate, and verifies the entanglement fidelity and Einstein nonlocality inequality.

Optionally, the Deutsch-Jozsa algorithm interface includes quantum computing circuit diagrams, encoding and detection methods, quantum state analysis and calculation results of four functions.

Based on the above technical solution, it can be seen that the multifunctional optical quantum computer teaching system of the present invention has at least one of the following beneficial effects compared with the prior art:

(1) This multifunctional optical quantum computer teaching system can demonstrate the most basic logic gate CNOT in quantum computing and measure the logical truth table under different basis vectors, so as to understand the most basic quantum computing elements.

(2) This multifunctional optical quantum computer teaching system can entangle two independent photons through a controlled NOT gate (CNOT), test the entanglement fidelity and the Einstein nonlocality (CHSH) inequality, and understand the role of quantum entanglement and quantum logic gates.

(3) This multifunctional optical quantum computer teaching system supports running the Deutsch-Jozsa algorithm, thereby understanding quantum computing acceleration.

(4) This multifunctional optical quantum computer teaching system can perform real-time programming of optical quantum computing circuits by using an optical quantum computing software operating system. Combined with quantum state detection and analysis functions, it can intuitively demonstrate the composition and computing functions of the multifunctional optical quantum computer.

(5) The invention is small in size, easy to operate, and easy to expand, making it very suitable for the teaching and demonstration of quantum computing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 schematically shows a system platform principle diagram according to an embodiment of the present invention;

FIG2 schematically shows a connection diagram of a system platform optical quantum computer device according to an embodiment of the present invention, wherein 2a is a fully automatic operation mode, and 2b is a manual operation mode;

FIG3 schematically shows a panel diagram of an optical quantum computing software operating system according to an embodiment of the present invention;

FIG4 schematically shows a circuit diagram of a CNOT optical quantum computing processor according to an embodiment of the present invention;

FIG5 schematically shows a circuit diagram of an optical quantum computing processor for demonstrating a constant function 1 of a Deutsch-Jozsa algorithm according to an embodiment of the present invention;

FIG6 schematically shows a circuit diagram of an optical quantum computing processor for demonstrating a constant function 2 of a Deutsch-Jozsa algorithm according to an embodiment of the present invention;

FIG7 schematically shows a circuit diagram of an optical quantum computing processor for demonstrating the Deutsch-Jozsa algorithm balance function 3 according to an embodiment of the present invention;

FIG8 schematically shows a circuit diagram of an optical quantum computing processor demonstrating the Deutsch-Jozsa algorithm balance function 4 according to an embodiment of the present invention.

DETAILED DESCRIPTION

The technical problem to be solved by the present invention is that the existing quantum computer system is complex in composition, huge in size, difficult to operate in practice, and cannot carry out extensive quantum computing experimental teaching. At the same time, domestic quantum computing experimental teaching is immature, lacks corresponding quantum computing teaching equipment, and the cognitive level of quantum computing is low, which further hinders the rapid development of quantum computing research. To this end, the present invention discloses a multifunctional optical quantum computer teaching system, which includes: an optical quantum computing software operating system and an optical quantum computer device. The optical quantum computing software operating system includes an optical quantum computer device connection diagram, a control NOT gate manipulation interface, and a Deutsch-Jozsa algorithm operation interface; the optical quantum computer device includes an optical quantum computing processor composed of lasers, nonlinear crystals, linear optical devices, quantum light sources, single-bit quantum gates and control NOT gates, and a quantum state measurement system, and the above devices are connected through an optical quantum computer device connection diagram. This teaching system can demonstrate the most basic logic gate CNOT of quantum computing and measure the logical truth table under different basis vectors, so as to understand the most basic quantum computing elements; it can entangle two independent photons through the CNOT gate, test the entanglement fidelity and CHSH inequality, and understand the role of quantum entanglement and quantum logic gates; it supports the running of the Deutsch-Jozsa algorithm, so as to understand quantum computing acceleration. By adopting the optical quantum computing software operating system, the optical quantum computing circuit can be programmed in real time, combined with the quantum state detection and analysis functions, the composition and computing functions of the multifunctional optical quantum computer can be intuitively demonstrated. The invention is easy to operate and conducive to expansion, and can be applied to teaching and demonstration in the field of quantum computing applications.

In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

As shown in Figure 1, it is a schematic diagram of the main structure of the present invention. The quantum light source is calculated by the optical quantum computing processor and then outputs the result. The optical quantum computing software control system analyzes the result and encodes the optical quantum computing processor to realize different computing functions.

The present invention proposes a multifunctional optical quantum computer teaching system. The system comprises: an optical quantum computing software operating system and an optical quantum computer device. The optical quantum computing software operating system comprises an optical quantum computer device connection diagram, a control NOT gate manipulation interface, and a Deutsch-Jozsa algorithm operation interface; the optical quantum computer device comprises an optical quantum computing processor composed of a laser, a nonlinear crystal, a linear optical device, a quantum light source, a single-bit quantum gate, and a control NOT gate, and a quantum state measurement system.

According to a further embodiment of the present invention, the optical quantum computer device connection diagram connects a quantum light source, an optical quantum computing processor composed of a single-bit quantum gate and a controlled NOT gate, and a quantum state measurement system to form a multifunctional optical quantum computer.

According to a further embodiment of the present invention, the quantum light source includes: a laser, optionally, for generating an initial pump light in the wavelength range of 300nm-450nm. The laser is a continuous or pulsed laser with a half-width range of 0.01-10nm. The quantum light source includes the laser light source including a focusing lens for focusing the pump light on a nonlinear crystal to generate a two-photon pair. The nonlinear crystal includes type 0 phase-matching crystals KTP, LN, MgLN, SLT, etc.; type I phase-matching and type II phase-matching crystals RTP, BBO, KTP, BiBO, SKTP, LN, CLBO, KTA, KDP, etc. The phase matching condition can be achieved by periodically polarized crystal design, angle or temperature control, etc. The polarization of the photon pair can be non-entangled or entangled. The structural design of the crystal can be beamlike or dual-ring, etc. The quantum light source used in the experiment is a two-way triggered single-photon source.

According to a further embodiment of the present invention, the optical quantum computing processor composed of the single-bit quantum gate and the controlled NOT gate includes a half-wave plate and a partial polarization beam splitter for rotating the polarization of photons and separating the paths.

According to a further embodiment of the present invention, the controlled NOT gate can entangle two independent photons.

According to a further embodiment of the present invention, the quantum state measurement system includes a half-wave plate, a quarter-wave plate, a polarization beam splitter, and a single-photon detector for performing tomographic measurement of the polarization state of photons.

According to a further embodiment of the present invention, some half-wave plates and quarter-wave plates of the optical quantum computing processor can be controlled by software to encode and measure the polarization state of photons.

According to a further embodiment of the present invention, the control NOT gate manipulation interface encodes the polarization states of two photons, measures the calculation results simultaneously, and finally outputs a logic truth table under different basis vectors.

According to a further embodiment of the present invention, the controlled NOT gate manipulation interface can encode the polarization states of two photons, form four maximum entangled states of two photons through a CNOT gate, and verify the entanglement fidelity and CHSH inequality.

According to a further embodiment of the present invention, the Deutsch-Jozsa algorithm interface includes quantum computing circuit diagrams, encoding and detection methods, quantum state analysis and calculation results of four functions.

As shown in Figure 2, it is a hardware connection diagram for optical quantum computing. In Figure 2a, 1 represents the quantum light source part, which is concentrated on the nonlinear crystal after the laser passes through the lens to obtain the photon pair of HV, and generates two-way triggered single photon source after passing through a polarization beam splitter. In this embodiment, the laser light of the laser is separated from the generated photon pair by a dichroic mirror. 2 represents the optical quantum computing processor part, which encodes the polarization state of the photon through R1, R2, R3, R4, and R5 through the optical quantum computing software control system, and controls whether the photon passes through the CNOT gate through a mechanically rotating reflector. 3 represents the optical quantum state analysis detection device, which measures the logical truth diagram under different basis vectors through R6, R7, R8, and R9. In order to facilitate the operator to manually operate the optical quantum computer, the manual adjustment capability of the corresponding mechanically rotated device can also be replaced with a purely manually operated device. The corresponding optical quantum computing hardware connection diagram is shown in Figure 2b.

As shown in Figure 3, it is the operation panel of the optical quantum computing software control system. The multifunctional optical quantum computer teaching system description tab lists the optical quantum computing hardware connection diagram, which is convenient for the operator to understand the hardware and functions of the optical quantum computer. The control NOT gate tab contains the optical quantum circuit description as shown in Figure 4. At the same time, the input state of the photon is encoded by R1, R2, R3, R4, and R5 to realize the function of the control NOT gate (CNOT), and finally the logical truth table is obtained after the quantum state measurement. When the photon encoded by R1 and R2 is (H or V, + or -), the entangled state of two photons can be generated, and then the CHSH inequality measurement can be performed. Exemplarily, Figure 3 corresponds to the operation panel of the Deutsch-Jozsa algorithm balance function 4. The optical quantum circuit programming, quantum state measurement and calculation results of the logic gate manipulation and algorithm demonstration are equipped with automatic and manual operation modes, which are convenient for the operator to understand the function and calculation process of the entire quantum computing, and further exercise the operator's experimental ability.

As shown in Figure 5-8, this is a circuit diagram of an optical quantum computing processor that demonstrates the constant function or balance function of the Deutsch-Jozsa algorithm in an embodiment. In order to demonstrate the Deutsch-Jozsa algorithm, four functions are encoded through an optical quantum computing circuit, and after calculation, the output result is finally used to determine whether the function is a constant function or a balance function. The circuit diagram shown in Figure 5-8 is the basic quantum circuit for implementing the Deutsch-Jozsa algorithm. The upper input bit is the control bit, and the lower input bit is the working bit. Through the H gate operation, the control bit becomes The target bit becomes The four functions are encoded as: I transformation; I transformation + single-bit NOT gate transformation (X); controlled NOT gate transformation (CNOT); controlled NOT gate transformation (CNOT) + single-bit NOT gate transformation (X). Finally, after another H gate operation, the working bit is restored to the quantum state |1>, and the control bit measurement result is 0 or 1. 0 means that the function is a constant function, and 1 means that the function is a balanced function. Through these algorithm demonstrations, operators can further understand the acceleration of quantum computing.

The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. A multifunctional optical quantum computer teaching system, characterized in that the teaching system includes an optical quantum computer device and an optical quantum computing software operating system; wherein, The optical quantum computing software operating system includes an optical quantum computer device connection diagram, a control NOT gate operation interface, and a Deutsch-Jozsa algorithm operation interface; The optical quantum computer device includes a quantum light source, an optical quantum computing processor and a quantum state measurement system; wherein the optical quantum computing processor and the quantum state measurement system are connected via the optical quantum computer device connection diagram; the optical quantum computing processor includes a single-bit quantum gate and a controlled NOT gate; The quantum light source includes a laser and a focusing lens, and the focusing lens is used to focus the pump light on a nonlinear crystal to generate a two-photon pair; the nonlinear crystal includes a type 0 phase matching crystal, a type I phase matching crystal, and a type II phase matching crystal; The control NOT gate manipulation interface encodes the polarization states of the two photons, measures the calculation results at the same time, and finally outputs the logic truth table under different basis vectors; The Deutsch-Jozsa algorithm interface includes quantum computing circuit diagrams, encoding and detection methods, quantum state analysis and calculation results of four functions; Among them, the four functions are encoded as: I transformation; I transformation + single-bit NOT gate transformation X; controlled NOT gate transformation CNOT; controlled NOT gate transformation CNOT + single-bit NOT gate transformation X. 2. The multifunctional optical quantum computer teaching system according to claim 1 is characterized in that the laser is used to generate initial pump light with a wavelength range of 300nm-450nm; the laser is a continuous laser or a pulsed laser with a half-width range of 0.01-10nm. 3. The multifunctional optical quantum computer teaching system according to claim 1 is characterized in that the quantum light source is a two-way triggered single photon source. 4. The multifunctional optical quantum computer teaching system according to claim 1 is characterized in that the optical quantum computing processor also includes a half-wave plate and a partial polarization beam splitter for rotating the polarization of photons and separating the paths. 5. The multifunctional optical quantum computer teaching system according to claim 1 is characterized in that the controlled NOT gate is used to entangle two independent photons. 6. The multifunctional optical quantum computer teaching system according to claim 1 is characterized in that the quantum state measurement system includes a half-wave plate, a quarter-wave plate, a polarization beam splitter and a single-photon detector, which are used to perform tomographic measurement of the polarization state of photons. 7. The multifunctional optical quantum computer teaching system according to claim 1 is characterized in that the control NOT gate manipulation interface encodes the polarization states of two photons, forms four maximum entangled states of two photons through the control NOT gate, and verifies the entanglement fidelity and Einstein nonlocality inequality.