Method and system for realizing entanglement gate in ion trap
By using multiple independently controllable Raman lights and adjusting the trapping voltage in the ion trap, multi-qubit parallel entanglement operation in the ion trap was realized, which solved the problem of difficulty in multi-qubit parallel entanglement in the prior art, shortened the quantum circuit time and improved the entanglement efficiency and fidelity.
Patent Information
- Application Number
- CN202511687395.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-02-13
AI Technical Summary
In the existing technology, it is difficult to achieve multi-qubit parallel entanglement operation in ion traps, which leads to the extension of quantum circuit time and the reduction of entanglement efficiency and fidelity.
By using multiple independently controllable Raman beams, which are focused onto different ions in the ion trap, parallel entanglement is achieved using two sets of radial phonon modes. The trapping voltage is adjusted to rotate the phonon modes to ensure that the superimposed wave vector is parallel to the phonon modes, thus avoiding crosstalk.
This enables multi-qubit parallel entanglement operations in an ion trap, shortening quantum circuit time and improving entanglement efficiency and fidelity.
Smart Images
Figure CN121528607A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of voltage signal control, in particular to a method and system for realizing entanglement gate in ion trap. BACKGROUND
[0002] Ion trap quantum computer is a computer that uses quantum mechanics principles for computation, and is considered as one of the most promising methods to realize scalable quantum computation, which has the potential to exceed traditional computers. In ion trap, two-qubit gates between different ions and quantum entanglement are widely implemented by Mølmer-Sørensen gate scheme, which realizes entanglement operation by regulating collective phonon modes of ions. For one-dimensional ion chain, these ions have two sets of radial phonon modes (i.e. radial phonon mode 1 and radial phonon mode 2 and one set of axial phonon mode , where N is the number of ions. In the process of realizing two-qubit entanglement of ion trap using Raman light, only one main radial phonon mode (such as one of Figure 1 ) is used, the laser frequency is , and the relationship between the two sets of radial phonon modes and the laser frequency is shown in Figure 1 . All phonon modes that are not perpendicular to the wave vector of Raman light will participate in the entanglement process and accumulate phase.
[0003] In common two-qubit entanglement operation, only one set of modes or interacts with the wave vector Δk of Raman light. However, this entanglement scheme using the same set of phonon modes still has difficulty in realizing parallel entanglement operation between multiple qubits, because in parallel entanglement operation, two pairs of entangled ions will simultaneously call the respective phonon modes in the same set to accumulate phase, resulting in mutual crosstalk, so that the evolution of quantum state in phase space cannot be closed, affecting the entanglement efficiency and fidelity. Therefore, this scheme only entangles one pair of ions at a time, and serially operates all two-qubit gates in a long quantum circuit. Because the time of two-qubit gate is much longer than that of single-qubit gate, the total time of quantum circuit is usually determined by the number of two-qubit gates. Serially operating all two-qubit gates will greatly prolong the time of time circuit, and the gate fidelity and result accuracy are more susceptible to external environmental interference and decrease. SUMMARY
[0004] The present application provides a method and system for realizing entanglement gate in ion trap, the method comprising:
[0005] A method for realizing entanglement gate in ion trap, the method comprising:
[0006] The laser emits multiple same-color lasers, including first Raman light, second Raman light and third Raman light, wherein the light intensity and frequency of each laser are independently controllable, and any single or multiple ions can be selectively focused and addressed;
[0007] The first Raman light is focused and irradiated into the ion trap, and the single or multiple ions in the ion chain are irradiated by the second Raman light after focusing, so that one or more single ions can perform a single-bit gate, or two ions can be entangled.
[0008] Meanwhile, the other second Raman light is focused and irradiated into the ion trap, and the single or multiple ions in the ion chain are irradiated by the third Raman light after focusing, so that one or more single ions can perform a single-bit gate, or two ions can be entangled.
[0009] Further, before the first Raman light, the second Raman light and the third Raman light irradiate the corresponding ions, they are first focused, wherein the diameter of the focused light spot is smaller than the distance between the two corresponding ions irradiated by the light beam, so as to realize the addressing operation of single ions and reduce the interference on the adjacent ions.
[0010] Further, the first Raman light is parallel to the third Raman light, and the second Raman light is perpendicular to the first Raman light.
[0011] Further, when the same ion is addressed, the first Raman light and the second Raman light are superimposed to form a first superimposed wave vector, and the other second Raman light and the third Raman light are superimposed to form a second superimposed wave vector, and the first superimposed wave vector and the second superimposed wave vector are perpendicular to each other.
[0012] Further, the method further comprises:
[0013] By adjusting the trapping voltage of the ion trap to rotate the direction of the phonon mode, the first superimposed wave vector and the second superimposed wave vector are parallel to the respective phonon mode.
[0014] Further, the first Raman light, the second Raman light and the third Raman light are respectively incident into the ion trap from different directions.
[0015] Further, the ion trap comprises four electrodes, namely a first electrode, a second electrode, a third electrode and a fourth electrode, wherein the first Raman light is incident between the second electrode and the third electrode, the second Raman light is incident between the third electrode and the fourth electrode, and the third Raman light is incident between the second electrode and the fourth electrode.
[0016] In another aspect, the present application also provides a system for implementing entanglement gates in an ion trap, the system comprising a laser and a control unit, wherein:
[0017] The laser emits a plurality of laser beams, including a first Raman light, a second Raman light and a third Raman light;
[0018] The control unit controls the first Raman light to be focused and irradiated into the ion trap to address one or more ions in the ion chain, and controls the second Raman light to be focused and irradiated to the one or more ions irradiated by the first Raman light, so that one or more single ions can perform a single-bit gate, or two ions can be entangled.
[0019] Meanwhile, the control unit controls another second Raman light to be focused and irradiated into the ion trap to address one or more ions in the ion chain, and controls the third Raman light to be focused and irradiated to the one or more ions irradiated by the another second Raman light, so that one or more single ions can perform a single-bit gate, or two ions can be entangled.
[0020] Further, when addressing the same ion, the first Raman light and the second Raman light are superimposed to form a first superimposed wave vector, and the another second Raman light and the third Raman light are superimposed to form a second superimposed wave vector, and the first superimposed wave vector and the second superimposed wave vector are perpendicular to each other.
[0021] Further, the system further comprises an adjusting unit, wherein,
[0022] The adjusting unit adjusts the direction of the trapped voltage phonon mode of the ion trap, so that the first superimposed wave vector and the second superimposed wave vector are parallel to the respective phonon mode.
[0023] The present application provides a method and system for implementing entanglement gates in an ion trap, which uses multiple groups of Raman light and two groups of radial modes to implement parallel gate operations between different ion pairs, greatly shortening the running time of quantum circuits. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0025] Figure 1 A diagram showing the relationship between the radial phonon mode and the laser frequency in the prior art;
[0026] Figure 2A flowchart of a method for realizing an entanglement gate in an ion trap according to an embodiment of the present application;
[0027] Figure 3 A schematic diagram of the first Raman light, the second Raman light and the third Raman light incident into the ion trap according to an embodiment of the present application;
[0028] Figure 4 A schematic diagram of the first Raman light, the second Raman light and the third Raman light incident into the ion trap according to an embodiment of the present application; Figure 3 A schematic diagram of the corresponding side view angle.
[0029] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION
[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.
[0031] It should be noted that all directional indications such as up, down, left, right, front, back, etc. in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture as shown in the drawings. If the certain posture changes, the directional indications also change accordingly.
[0032] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features indicated or the number of the technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features.
[0033] As shown in the drawings, the present application provides a method for realizing an entanglement gate in an ion trap, the method comprising: Figure 2
[0034] The laser emits a plurality of same-color lasers, including a first Raman light, a second Raman light and a third Raman light, wherein the light intensity and frequency of each laser are independently controllable, and any single or multiple ions can be selectively focused and addressed;
[0035] The single or multiple ions in the ion chain are irradiated by the first Raman light after focusing, and the single or multiple ions irradiated by the first Raman light are irradiated by the second Raman light after focusing, so that one or more single ions can be simultaneously subjected to single-bit gate operation, or two ions can be entangled;
[0036] Meanwhile, the single or multiple ions in the ion chain are irradiated by the second Raman light focused after irradiation into the ion trap, and the single or multiple ions irradiated by the second Raman light are irradiated by the third Raman light focused after irradiation, so that one or more single ions can be simultaneously subjected to single-bit gates, or two ions can be entangled.
[0037] The present application will be described in detail below.
[0038] In some embodiments of the present application, as shown in Figure 3 The ion trap includes four electrodes, i.e., a first electrode, a second electrode, a third electrode and a fourth electrode, wherein the first Raman light, the second Raman light and the third Raman light are incident into the ion trap from different directions, i.e., the first Raman light is incident between the second electrode and the third electrode, the second Raman light is incident between the third electrode and the fourth electrode, and the third Raman light is incident between the second electrode and the fourth electrode; the first electrode and the third electrode are DC electrodes, and the second electrode and the fourth electrode are RF electrodes, or the first electrode and the third electrode are RF electrodes, and the second electrode and the fourth electrode are DC electrodes.
[0039] In some embodiments of the present application, the beam spot diameters of the first Raman light, the second Raman light and the third Raman light emitted by the laser are all smaller than the distance between two corresponding ions irradiated by the beams, so as to realize the addressing operation of a single ion and reduce the interference with adjacent ions.
[0040] In some embodiments of the present application, as shown in Figure 3 and Figure 4 The first Raman light is parallel to the third Raman light, and the second Raman light is perpendicular to the first Raman light.
[0041] In some embodiments of the present application, when the optical addressing operation is performed on the same ion, the first Raman light and the second Raman light are superimposed to form a first set of superimposed wave vectors, and the second Raman light and the third Raman light are superimposed to form a second set of superimposed wave vectors, and the first set of superimposed wave vectors and the second set of superimposed wave vectors are perpendicular to each other. By adjusting the trapping voltage of the ion trap to rotate the direction of the phonon mode, the first set of superimposed wave vectors and the second set of superimposed wave vectors are perpendicular to each other and parallel to the respective phonon modes.
[0042] In addition, an example of two pairs of ions subjected to parallel pre-generated entanglement in the present application is provided, and the two pairs of ions subjected to parallel pre-generated entanglement in the present application are described as follows. Figure 4As shown in the figure, one pair of pre-generated entangled ions is determined after focusing of two beams of incident first Raman light and two beams of incident second Raman light, wherein the beam spot diameters are less than the spacing between the two corresponding ions to be irradiated, so as to achieve addressing operation on single ions and reduce interference on adjacent ions; another pair of pre-generated entangled ions is determined after focusing of third Raman light and two other beams of second Raman light, wherein the beam spot diameters are less than the spacing between the two corresponding ions to be irradiated, so as to achieve addressing operation on single ions and reduce interference on adjacent ions.
[0043] One pair of pre-generated entangled ions is determined after focusing of two beams of incident first Raman light and two beams of incident second Raman light, including: the two beams of first Raman light irradiate ion A and ion B in Figure 4 respectively, and the two beams of second Raman light irradiate ion A and ion B in Figure 4 respectively. Ion A and ion B are two adjacent or non-adjacent ions, and ion A and ion B are two pre-generated entangled ions. And the wave vector of the superposition of the first Raman light and the second Raman light acts on ion A, and similarly, ion B will also be acted on by the wave vector of the superposition of the first Raman light and the second Raman light , wherein ion A itself generates two-direction phonon modes and in the ion trap by the electric field, and the radial phonon mode is rotated by adjusting the trapping voltage of the ion trap, so that the direction of the final phonon mode is parallel to the direction of the superposition wave vector .
[0044] Another pair of pre-generated entangled ions is determined after focusing of two beams of incident second Raman light and two beams of incident third Raman light, including: the two beams of second Raman light irradiate ion C and ion D in Figure 4 respectively, and the two beams of third Raman light irradiate ion C and ion D in Figure 4 respectively. Ion C and ion D are two adjacent or non-adjacent ions, and ion C and ion D are two pre-generated entangled ions. And the wave vector of the superposition of the second Raman light and the third Raman light acts on ion C, and similarly, ion D will also be acted on by the wave vector of the superposition of the second Raman light and the third Raman light , wherein ion C itself generates two-direction phonon modes and in the ion trap by the electric field, and the radial phonon mode is rotated by adjusting the trapping voltage of the ion trap, so that the direction of the final phonon mode is parallel to the direction of the superposition wave vector .
[0045] In this embodiment, the superimposed wave vector of the first Raman light and the second Raman light cannot excite the phonon mode in the direction, so the first Raman light and the second Raman light cannot use the mode to generate entanglement between ions, but can only use the mode to generate entanglement between ions. The same superimposed wave vector of the second Raman light and the third Raman light cannot excite the phonon mode in the direction, so the second Raman light and the third Raman light cannot use the mode to generate entanglement between ions, but can only use the mode to generate entanglement between ions.
[0046] Therefore, using this principle, two groups of phonon modes can be excited simultaneously by using different Raman light combinations, and entanglement of two groups of different ions can be achieved without affecting each other. The first Raman light and the second Raman light only use the mode to address and pre-entangle the ion pair (A, B), and the second Raman light and the third Raman light only use the mode to address and pre-entangle the ion pair (C, D), so as to achieve parallel entanglement operation, shorten the running time of the line and improve the efficiency.
[0047] The above example is to form parallel entanglement between two ion pairs, so as to realize parallel two-bit gates. The functions that can be realized by the present application include:
[0048] 1. Parallel single-bit and two-bit gates can be performed. Since the laser frequencies and control times required by single-bit and two-bit gates are inconsistent, single-bit and two-bit gates in the line of the conventional scheme are usually also performed in series. In the present application, single-bit and two-bit gates can be operated in parallel. For example, the first Raman light and the second Raman light operate on one pair of ions (A, B) in the ion chain to realize a two-bit gate, and another second Raman light and third Raman light operate on the remaining one at the same time, such as any one of ions C, D, E and F in Figure 4 to perform a single-bit gate, or multiple ions, such as single ions C and D in to perform multiple single-bit gates.
[0049] 2. Three-bit gates are realized. One pair of ions, such as ion pair (A, B), is entangled using the first Raman light and the second Raman light, and ion pair (B, C) is entangled using the second Raman light and the third Raman light to realize a Toffoli gate.
[0050] 3. To accelerate an existing two-qubit gate, the first and second Raman beams, along with the second and third Raman beams, are simultaneously applied to the ion pair (A,B). Since independent phonon modes are used and phase accumulation is performed separately, the gate speed can be increased.
[0051] On the other hand, the present invention also provides a system for realizing an entanglement gate in an ion trap, the system comprising a laser and a control unit, wherein:
[0052] The control unit controls the first Raman light to focus and irradiate one or more ions in the ion trap, and at the same time, the second Raman light focuses and irradiates the single or multiple ions irradiated by the first Raman light, so that the single ion can perform a single-qubit gate, or the multiple ions can generate pre-entangled ion pairs.
[0053] Simultaneously, the control unit controls another second Raman beam to focus and irradiate one or more ions in the ion trap, while the third Raman beam focuses and irradiates another second Raman-irradiated single or multiple ions, so that one or more single ions can perform a single-bit gate, or multiple ions can generate pre-entangled ion pairs.
[0054] In some embodiments of the present invention, the system further includes an adjustment unit, wherein the trapping voltage of the ion trap is adjusted by the adjustment unit to rotate the direction of the phonon mode, such that the first superimposed wave vector and the second superimposed wave vector are parallel to their respective phonon modes.
[0055] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made under the concept of the present invention using the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.
Claims
1. A method of implementing an entangling gate in an ion trap, characterized by, The method comprises: a plurality of lasers are emitted by the laser, including first Raman light, second Raman light and third Raman light, wherein the light intensity and frequency of each laser are independently controllable, and any single or multiple ions can be selectively focused and addressed; the first Raman light is focused and irradiated into the ion trap, and the single or multiple ions in the ion chain are irradiated, and the second Raman light is focused and irradiated to the single or multiple ions irradiated by the first Raman light, so that one or more single ions can perform a single-bit gate, or two ions are entangled to form a two-bit gate; at the same time, the other second Raman light is focused and irradiated into the ion trap, and the single or multiple ions in the ion chain are irradiated, and the third Raman light is focused and irradiated to the single or multiple ions irradiated by the other second Raman light, so that one or more single ions can perform a single-bit gate, or two ions are entangled to form a two-bit gate.
2. A method of implementing an entangling gate in an ion trap as claimed in claim 1, characterized in that, Before the first Raman light, the second Raman light and the third Raman light irradiate the corresponding ions, the light beams are focused, wherein the diameters of the focused light spots are all smaller than the distance between the two corresponding ions irradiated by the light beams, so as to realize the addressing operation of the single ion and reduce the interference on the adjacent ions.
3. A method of implementing an entangling gate in an ion trap as defined in claim 1, characterized in that, The first Raman light and the third Raman light are parallel, and the second Raman light and the first Raman light are perpendicular to each other.
4. The method of claim 1, wherein the method is implemented in an ion trap. When the same ion is addressed, the first Raman light and the second Raman light are superimposed to form a first superimposed wave vector, and the other second Raman light and the third Raman light are superimposed to form a second superimposed wave vector, and the first superimposed wave vector and the second superimposed wave vector are perpendicular to each other.
5. A method of implementing an entangling gate in an ion trap as defined in claim 3, characterized in that, The method further comprises: by adjusting the trapping voltage of the ion trap to rotate the direction of the phonon mode, the first superimposed wave vector and the second superimposed wave vector are parallel to the respective corresponding phonon mode.
6. A method of implementing an entangling gate in an ion trap as claimed in claim 5, characterized in that, The first Raman light, the second Raman light and the third Raman light are respectively incident into the ion trap from different directions.
7. A method of implementing an entangling gate in an ion trap as claimed in claim 6, characterized in that, The ion trap comprises four electrodes, namely a first electrode, a second electrode, a third electrode and a fourth electrode, wherein the first Raman light is incident between the second electrode and the third electrode, the second Raman light is incident between the third electrode and the fourth electrode, and the third Raman light is incident between the second electrode and the fourth electrode.
8. A system for implementing an entangling gate in an ion trap, characterized by, The system comprises a laser and a control unit, wherein: a plurality of lasers are emitted by the laser, including first Raman light, second Raman light and third Raman light; the first Raman light is controlled by the control unit to be focused and irradiated into the ion trap, and the single or multiple ions in the ion chain are irradiated, and the second Raman light is controlled by the control unit to be focused and irradiated to the single or multiple ions irradiated by the first Raman light, so that one or more single ions can perform a single-bit gate, or two ions are entangled to form a two-bit gate; at the same time, the other second Raman light is controlled by the control unit to be focused and irradiated into the ion trap, and the single or multiple ions in the ion chain are irradiated, and the third Raman light is controlled by the control unit to be focused and irradiated to the single or multiple ions irradiated by the other second Raman light, so that one or more single ions can perform a single-bit gate, or two ions are entangled to form a two-bit gate.
9. A method and system for implementing an entangling gate in an ion trap as claimed in claim 8, wherein, When addressing the same ion, the first Raman light and the second Raman light superimpose to form a first superimposed wave vector, and the further second Raman light and the third Raman light superimpose to form a second superimposed wave vector, the first superimposed wave vector and the second superimposed wave vector being perpendicular to each other.
10. The method and system for implementing entangling gates in an ion trap as claimed in claim 9 wherein, The system further comprises an adjusting unit, wherein The direction of the trapped voltage rotational phonon mode of the ion trap is adjusted by the adjusting unit such that the first superimposed wave vector and the second superimposed wave vector are parallel to the respective corresponding phonon mode.